Operating Instructions Capacitive electrodes EK mA by benbenzhou

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									                           Level and Pressure




Operating Instructions
Capacitive electrodes EK
4 … 20 mA - Compact
                                                                                  Safety information




Safety information                                       Note Ex area
Please read this manual carefully, and also take    Please note the attached safety instructions con-
note of country-specific installation standards     taining important information on installation and
(e.g. the VDE regulations in Germany) as well       operation in Ex areas.
as all prevailing safety regulations and accident   These safety instructions are part of the operat-
prevention rules.                                   ing instructions manual and come with the Ex
For safety and warranty reasons, any internal       approved instruments.
                                                                                                         22574-EN-020809




work on the instruments, apart from that involved
in normal installation and electrical connection,
must be carried out only by qualified VEGA per-
sonnel.

2                                                         Capacitive electrodes EK 4 … 20 mA - Compact
                  Contents


                  Contents

                      Safety information ......................................................................... 2
                      Note Ex area ................................................................................. 2

                  1   Product description
                      1.1 Function and configuration ................................................... 4
                      1.2 Types and versions .............................................................. 5
                      1.3 Technical data ....................................................................... 7
                      1.4 Approvals ........................................................................... 12
                      1.5 Dimensions ......................................................................... 13
                      1.6 Type plate ........................................................................... 15

                  2   Mounting
                      2.1 Mounting instructions ......................................................... 16

                  3   Electrical connection
                      3.1 Connection instructions ...................................................... 20
                      3.2 Wiring plan .......................................................................... 20

                  4   Setup
                      4.1 General adjustment ............................................................ 24
                      4.2 Adjustment - Oscillators
                          CAP E32 Ex and CAP E32 H Ex ........................................ 25
                      4.3 Adjustment with VVO .......................................................... 28
                      4.4 Adjustment with HART® handheld ...................................... 29

                  5   Diagnosis
                      5.1 Simulation ............................................................................ 36
                      5.2 Maintenance ........................................................................ 36
                      5.3 Repair .................................................................................. 36
                      5.4 Fault rectification ................................................................. 37
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                  Capacitive electrodes EK 4 … 20 mA - Compact                                                           3
                                                                              Product description


1 Product description
                                                  The electrode and the vessel wall are the
1.1 Function and configuration
                                                  capacitor surfaces. The medium is the dielec-
                                                  tric. Due to the higher dielectric constant (DK
Capacitive electrodes series EK can detect
                                                  value) of the medium with respect to air, the
the level of practically any kind of product,
                                                  capacitance of the capacitor increases as the
regardless of whether it is a liquid, powder or
                                                  level rises around the electrode.
paste. This also applies to adhesive products.

The electrode simultaneously measures the
capacitance and the ohmic resistance (admit-
tance processing). By this means, even diffi-
cult products such as adhesive, conductive
substances and solids with fluctuating mois-
ture content can be measured.

Through the use of screening tubes and
screening segments, inactive areas can be
created on the probe where pollution, conden-
sation or permanent buildup cannot influence
the measuring result.
                                                  Fig. 1.2 Capacitance change through varying
                                                  immersion level
Measuring principle
Electrode, medium and vessel wall form an         The capacitance change is processed by the
electrical capacitor.                             oscillator and converted into a level-propor-
                                                  tional measured value. The measured value is
The capacitance of the capacitor is generally     outputted as a standardised, floating
influenced by three factors:                      4 … 20 mA analogue signal, or optionally as a
- distance between electrode surfaces (a)         digital signal with the HART® communication
- size of the electrode surfaces (b)              protocol. The sensor can be adjusted through
- type of dielectric between the electrodes (c)   the integrated oscillator. As an option, adjust-
                                                  ment is also possible with a HART® handheld
                            a
                                                  or PC.

                                                  In continuous level measurement, the level is
                                    b             continuously detected and converted into a
                                                  level-proportional signal which is either directly
                                                  displayed or further processed.

    c                                             For this type of measurement, you need a
                                                  capacitive electrode series EK with oscillator
Fig. 1.1 Plate capacitor (schematic drawing)      CAP E32 Ex or CAP E32 H Ex.

                                                  Continuous measurement requires a constant
                                                  dielectric value εr i.e. the medium should have
                                                  unchanging properties.
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4                                                       Capacitive electrodes EK 4 … 20 mA - Compact
                  Product description


                  1.2 Types and versions
                                       Type*)             EK            EK            EK            EK

                  Version                                 11            21            24            26
                  Level detection 3)                       •             •             •             •
                  Continuous                               •             •             •
                  Partly insulated                         •
                  Fully insulated                                        •             •             •


                  Oscillators
                  CAP E32 Ex                               •             •             •             •
                  CAP E32 H Ex                             •             •             •             •

                  Approvals
                  ATEX II 1G, 1/2G EEx ia IIC T6           •             •             •             •
                  Overfill protection acc. to WHG          •             •             •             •
                  German Lloyd 1)                          •             •             •             •
                  Lloyds Register of Ship 1)               •             •             •             •
                  American Bureau of Ship 1) •             •             •             •
                  Bureau Veritas 1)                        •             •             •             •
                  RINA 1)                                  •             •             •             •

                  Process fitting
                  G¾A                                      •             •             •             •
                  G1A                                      •             •             •             •
                  ¾ NPT                                    •             •             •             •
                  1 NPT                                    •             •            •              •
                  Flange plated                                          •

                  Electrode material
                  Steel                                                  •
                  Stainless steel 1.4435                  •2)            • 2)         • 3)          • 4)

                  Insulation material 2)
                  PTFE                                     •             •                           •
                  FEP                                                                 •
                  PE                                       •             •

                  Concentric tube
                  Steel                                    •             •
                  Stainless steel (1.4435)                               •            •
                  *) All instrument types, also Ex0
                  1) applied for
22574-EN-020809




                  2) For electrodes certified for Ex-Zone 0, ATEX II 1/2G EEx ia IIC T6 has only approved PTFE and FEP as insulation
                     materials.
                  3) Level detection with signal conditioning instrument possible.




                  Capacitive electrodes EK 4 … 20 mA - Compact                                                                         5
                                                                                            Product description


                             Type*)     EK            EK            EK            EK
Version                                 11            21            24            26
Screening tube (option)
Stainless steel 1.4435                   •             •

Temperature
adapter (option)
Stst (1.4435) max. 200°C                 •             •                           •

Housing material
Plastic (IP 66)                          •             •             •             •
Aluminium - plastic coated
(IP 66 / 67)                             •             •             •             •

Misc.
Overvoltage protection option
(integrated)                             •             •             •             •
Angled electrode 4)                      •            • 5)

*) All instrument types, also Ex0
1) applied for
2) For electrodes certified for Ex-Zone 0, ATEX II 1/2G EEx ia IIC T6 has only approved PTFE and FEP as insulation
   materials.
4) Bending max. 90°
5) EK 21 only in PTFE with 3.2 mm insulation thickness




                                                                                                                     22574-EN-020809




6                                                                  Capacitive electrodes EK 4 … 20 mA - Compact
                  Product description


                  1.3 Technical data
                  Housing
                     Housing material                            plastic PBT (Polyester) or Aluminium
                                                                 plastic coated
                     Protection
                     - plastic housing                           IP 66
                     - Aluminium housing                         IP 66 and 67 (meets requirements of both pro-
                                                                 tection types)
                     Cable entry                                 1 piece M20 x 1.5
                     Terminals                                   for max. 1.5 mm2 wire cross-section

                  Process fitting
                     Material                                    steel 1.4435 (316 L)
                     Thread                                      G ¾ A or ¾ NPT
                                                                 G 1 A or 1 NPT
                     Flange                                      flange versions, plated

                  Electrode
                     Material (rod)
                     - EK 11                                     1.4435 (316 L)
                     - EK 21                                     steel (St 37), 1.4435 (316 L)
                     - EK 24                                     1.4401 (316 L)
                     - EK 26                                     steel
                     Length
                     - rod                                       max. 3 m
                     Insulation                                  see "Insulation materials"

                  Ambient conditions
                     Ambient temperature on the housing          -40°C … +80°C
                     Product temperature                         see "Product temperature and operating
                                                                 pressure"
                     Storage and transport temperature           -40°C … +80°C
                     Operating pressure                          see "Product temperature and operating
                                                                 pressure"
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                  Capacitive electrodes EK 4 … 20 mA - Compact                                                   7
                                                                                           Product description

Oscillators CAP E32 Ex, CAP E32 H Ex
    Protection class                                 II
    Overvoltage category                             III
    Frequency                                        300 KHz
    Capacitance ranges                               0 … 3000 pF

    Power supply                                     12 … 36 V DC
                                                     for Ex applications note the permissible electrical
                                                     connection values stated in the certificate.
    Permissible residual ripple                      USS ≤ 1 V
    Potential separation                             min. 500 V DC

Weight
                                                     Load in
                                                     Ohm
                                                           1000



                                                               800



                                                           600


                                                               200
                                                                                                     Power supply
                                                                                                     in V
                                                                12      18     24    30    36


    Basic weight (e.g. EK 24)                        approx. 0.8 kg
    Rod weight                                       ø 6 mm - 0.23 kg/m
                                                     ø 10 mm - 0.62 kg/m




Oscillators in two-wire technology for capacitive electrodes EK
Type        Application                              Meas. range               Frequency        Signal condit.
                                                                                                instrument
CAP E32     Compact electronics 4 … 20 mA for        0 - 3000 pF               300 KHz          not necessary
Ex          continuous level measurement,
            acc. to the principle of phase-
            selective admittance processing.
            Parameter adjustment via key pushing
            on the oscillator
CAP E32     Compact electronics 4 … 20 mA for        0 - 3000 pF               300 KHz          not necessary
HEx         continuous level measurement,
            acc. to the principle of phase-
            selective admittance processing.
                                                                                                                    22574-EN-020809




            Parameter adjustment via key pushing
            on the oscillator, VVO from V. 2.30 or
            HART® handheld




8                                                                    Capacitive electrodes EK 4 … 20 mA - Compact
                  Product description


                  Oscillator                                        the fully and partly insulated electrodes react
                                                                    differently (see also „Fig. 1.3 Varying moisture
                  The oscillator CAP E32 (H) Ex with patented       content“). Whereas the measured value from
                  processing (phase-selective admittance            fully insulated electrodes increases with un-
                  processing) extends the area of application of    changing product level, the measured value
                  capacitive level measurement technology. This     from partly insulated electrodes falls.
                  function can be switched on, see 4 Setup.
                                                                         Level
                                                                                                             fully insulated
                                                                         Measured value
                  In conjunction with a fully insulated rod elec-                                            electrode
                  trode, the oscillator also compensates heavy                                   15 % vol.
                  conductive buildup.                                    +
                                                                    1)
                  Mounted with any rod or cable electrode type           - 0%      5%     10 %                   Solid
                                                                                                                 moisture (%)
                  EK, this oscillator also enables exact measure-
                  ment of solids with varying moisture content.
                                                                                                             partly insulated
                                                                                                             electrode
                  The oscillator processes the measuring cur-       1) Real value level
                  rents acc. to their phase position. Measuring
                  currents with a defined phase shift, commonly     Fig. 1.3 Varying moisture content
                  occurring when buildup forms or moisture
                  content changes, are hence filtered out.


                  Varying moisture content

                  A change of moisture content in solids causes
                  a change of the dielectric constant (er). A
                  simultaneous change of the ohmic resistance
                  of the product also occurs. In addition, the
                  change causes a phase shift of the measuring
                  currents.

                  With capacitive measurement, even minor
                  changes of moisture content cause measure-
                  ment errors. Typical products are e.g. sand,
                  aggregate in the cement industry, hops or
                  plastic granules (after drying).

                  When using oscillator CAP E32 (H) Ex,
                  changes of moisture content up to 15 % vol.
                  do not influence the accuracy of the measure-
                  ment. Even layers containing different
                  amounts of moisture do not affect the accu-
                  racy.

                  If the moisture content goes above 15 % vol.,
22574-EN-020809




                  Capacitive electrodes EK 4 … 20 mA - Compact                                                                  9
                                                                                                    Product description


Product temperature1) and operating
pressure1)                                                                 bar                                           1
The numbers in the tables all relate to the                                 40                           EK 21: up to 16 bar
graphs on this page. The stated pressures
                                                                    16
are valid for screw connections G ¾ A, ¾ NPT,
G 1 A, 1 NPT.                                                       -30          0     60   80 ˚C

When using flanged versions, make sure to
note their nominal pressure. All electrodes are
also suitable for applications in a vacuum (-
1 bar).
                                                                           bar

                                                                            63
                                                                                                          EK 42:
                                                                                                                         2
For electrodes certified for Ex-Zone 0, only
                                                                            40                            up to 16 bar
PTFE and FEP are approved as insulating                                                                   EK 24:
materials.                                                                  16                            from 100°C 6 bar,
                                                                                                          max. 150°C for
                                                                                               100 ˚C
                                                                                                          30 min.
Process fitting, 1.4435                                       -50                0




        Insulation
                            PTFE

                                   FEP




                                                                                                                          3
                       PE




                                                                           bar
Electrode type                                                             63

EK 11                  1    3      -
                                                                           40
EK 21                  1    3      -                                       25

EK 21 with flange      -    2      -
EK 24                  -     -     2                         -50                 0              100                    200 ˚C
                                                                                                      Temperature adapter
EK 26                  1    3      -




                                                                                                                                22574-EN-020809




1) For Ex applications, the permissible temperatures and pressures stated in the certificate must be noted. Please
   observe the table on the following page.

10                                                                       Capacitive electrodes EK 4 … 20 mA - Compact
                  Product description

                  Electronics temperature

                  Product and ambient temperatures must be
                  kept at levels that do not exceed the limit
                  temperature of the electronics.


                  Temperature classes T4 (or no Ex)

                  Without temperature adapter
                  - product temperature            -40°C … +135°C
                  - ambient temperature1)          -40°C … +90°C



                  Temperature class T3
                  With temperature adapter
                                                             Plastic housing   Metal housing

                  Product temperature            -40°C …     180°C     200°C   150°C   175°C   200°C
                                           )
                  Ambient temperature            -40°C …     80°C      75°C    80°C    69°C    58°C
22574-EN-020809




                  1) Ambient temperature on the oscillator

                  Capacitive electrodes EK 4 … 20 mA - Compact                                         11
                                                                                Product description


1.4 Approvals                                       Ship approvals
                                                    For use on ships, type approval certificates
Explosion protection                                are available from several ship classification
Only certified capacitive electrodes EK** Ex 0      authorities (GL, LRS, ABS, BV, RINA).
may be used in hazardous areas with com-
bustible gases, vapours or fog.
Capacitive electrodes EK** Ex 0 are suitable        CE approval
for use in hazardous areas of zone 1 and            The capacitive electrodes EK meet the protec-
zone 0.                                             tive regulations of EMC (89/336/EWG) and
The explosion protection provided by these          NSR (72/23/EWG). Conformity has been
instruments is certified by the EC type ap-         judged acc. to the following standards:
proval and the conformity certificate, possibly     EMC          Emission       EN 50 081 - 1
with national zone 0 annex, issued by the                        Susceptibility EN 50 082 - 2
approval authority. These documents are             NSR                         EN 61 010 - 1
generally attached to the instruments.
When the capacitive electrodes are mounted
and operated in hazardous areas, the Ex             Zone 2
installation regulations must be noted.             According to DIN VDE 0165, instruments can
The information and regulations in the sup-         be used in hazardous areas of zone 2 without
plied certificates (EC type approval certificate,   approval; they must meet the requirements in
conformity certificate) of the capacitive elec-     section 6.3 of this VDE. The compliance of the
trodes as well as of the accompanying de-           instruments with these requirements is con-
vices (signal conditioning instrument,              firmed by VEGA in a manufacturer declaration.
separator, safety barrier) must be noted.

• As a rule, the installation of Ex systems
  must be carried out only by qualified per-
  sonnel.
• The capacitive electrodes must be powered
  from an intrinsically safe circuit; the permis-
  sible electrical values are stated in the
  accompanying certificate.
• Capacitive electrodes with electrostatically
  chargeable plastic parts come with a warn-
  ing label informing of measures to be taken
  to avoid the dangers of electrostatic dis-
  charges. Note the information on the warn-
  ing label.
• The explosion protection of the instrument
  used is only ensured when the limit tem-
  peratures stated in the certificate are not
  exceeded.
• In case of danger due to oscillation or vibra-
  tion, the appropriate parts of the capacitive
  electrodes must be protected.
• After shortening the electrode cable, make
  sure the gravity weight is sufficiently se-
  cured by means of the pins.
                                                                                                         22574-EN-020809




12                                                        Capacitive electrodes EK 4 … 20 mA - Compact
                  Product description


                  1.5 Dimensions
                  Dimensions of capacitive electrodes type EK … Ex 0
                  Type EK 11 (partly insu-                         EK 11 with concentric tube               Type EK 21 (fully insulated)
                  lated)                                                           85
                                               32,5                                           32,5
                                 85                                                                                                     32,5
                                                                                                                          85




                                                                       90
                   90




                                                                                                             90
                                                                                                  M20x1,5
                                                  M20x1,5                                                                                 M20x1,5

                                                                       35
                   35




                                                                                            SW 41




                                                                                                             35
                                              SW 41                         20
                                                                                                                                      SW 41
                                                                                          G ¾ A or G
                         20




                                            G ¾ A or G                                                                             G ¾ A or G




                                                                                                                  20
                                                                                          1A
                                            1A                                                                                     1A
                         50




                                       A
                                                                       L
                   L




                                                                                                             L
                                                                                                                               A
                                       B




                                                                                 ø21,3
                                                                                                            L (min. 100 mm, max. 3000 mm)
                  L (min. 100 mm, max. 3000 mm)



                  EK 21 with concentric tube                       Type EK 24 (fully insulated,
                                                                   for very adhesive products)
                                 85            32,5
                                                                                  85         32,5
                  90




                                                                    90




                                                 M20x1,5
                                                                                               M20x1,5
                  35




                                             SW 41
                                                                    35




                                           G ¾ A or G                                     SW 41
                        20




                                           1A
                                                                                         G ¾ A or G
                                                                         20




                                                                                         1A
                  L




                                                                   L




                               ø21,3                                             ø14,4

                  L (min. 100 mm, max. 3000 mm)                    L (min. 120 mm, max. 3000 mm)
22574-EN-020809




                  Insulation                 A               B
                                           Outer-ø         Rod-ø
                  PE   2.0 mm               14 mm        10 mm
                  PTFE 2.0 mm               10 mm        6 mm
                  PTFE 2.0 mm               14 mm        10 mm



                  Capacitive electrodes EK 4 … 20 mA - Compact                                                                                      13
                                                                                                                                                    Product description


Housing

                                                  85                32,5
                              90




                                                                       M20x1,5




Housing of plastic / Aluminium


Temperature adapter




                                                  SW 41
                              133




                                                      SW 41
                              20




                                                  G 3/4 A or G1 A

of 1.4435




Concentric tube                                                            Screening tube
                                         SW 60                                                                SW 60


                                                                                                                 of 1.4435 with closing
                                          of 1.4435
                                                                             L (min. 75/max. 2000 mm)




                                                                                                                 cone of PTFE (Lmax.
  L (min. 100/max. 4000 mm)




                                                                                                                 = electrode length
                                                                                                                 minus 140 mm)



                                                                                                        ø38

                                                                                                              Closing cone
                                   ø38
                                                                             10




                                                                                                                                                                             22574-EN-020809




14                                                                                                                            Capacitive electrodes EK 4 … 20 mA - Compact
                  Product description


                  1.6 Type plate                                  Contents of the type plate (example)

                  Before mounting and electrical connection,               VEGA® EK 11
                  please make sure you are using a suitable       1        type EK11EXO.XGBVSTXXVKXX
                  instrument. Note the type plate which is lo-             see PTB Nr. EX-98.E.2085 EEx ia IIC T6          0032       9
                  cated as shown below:                           2
                                                                           PTB 98 ATEX 2086       II 1/2G EEx ia IIC T6
                                                                  3        techn. data see document. / certificates        1998       8
                                                                           protection:    IP 66/67 Insp.
                                                                           length: 400mm          VVO: 02           ser. no. 10612892
                                            Type plate            4        Ord. no. 123456/000
                                                                                      ®
                                                                                        D-77757 Schiltach

                                                                                                                    5        6
                                                                                     Z-65.13.XXX
                                                                                                         7

                                                                  1 Master data of the order number
                                                                  2 Ex certification number
                  The type plate contains important data re-        Explosion protection version - note the information
                  quired for mounting and connection. The con-      and regulations of the certificate
                  figuration and elements of the type plate are   3 Data of the electronics / Approvals
                  hence explained in the following example.       4 No. of the order confirmation/Pos. no.
                                                                  5 Number of the electrode type
                                                                  6 Serial number
                                                                  7 Test mark when used as part of an overfill protection
                                                                    system for vessels storing water endangering liquids
                                                                    - note the information and regulations of the general
                                                                    type approval
                                                                  8 Year of manufacture
                                                                  9 Number of the test authority



                                                                  Order code
                                                                  You can find detailed information on the order
                                                                  code in the product information manual „Ca-
                                                                  pacitive“ or in the „VEGA Price list“.
22574-EN-020809




                  Capacitive electrodes EK 4 … 20 mA - Compact                                                                   15
                                                                                           Mounting


2 Mounting
2.1 Mounting instructions                           Pressure
                                                    If there is gauge pressure or underpressure
                                                    in the vessel, the mounting boss on the thread
General
                                                    must be sealed. Use the attached seal ring.
Different mediums and measurement require-
                                                    Check whether the seal ring is resistant
ments make different installation positions
                                                    against the medium.
necessary. Please note the following points.
                                                    Insulating measures, such as e.g., covering
                                                    the thread with Teflon tape, can obstruct the
Lateral load                                        necessary electrical connection. in such
Make sure that the electrode is not subjected       cases, make sure the instrument has a
to strong lateral forces. Mount the electrode in    ground connection to the vessel.
a position in the vessel where no disturbing
factors, e.g. stirrers, filling openings etc. are
present. This is especially important for very      Shortening the electrode
long rod and cable electrodes.
                                                    Fully insulated electrodes have fixed dimen-
                                                    sions which must not be modified in any way.
                                                    Any modification will destroy the instrument.

                                                    Partly insulated cable or rod electrodes can
                                                    be shortened if necessary. The basic capaci-
                                                    tance of the electrodes is compensated auto-
                                                    matically at adjustment time. Because of this,
                                                    the electrodes can be shortened by any de-
                                                    sired amount.

                                                    Cable electrode EK 31 can also be shortened
                                                    (see fig. 2.2). Loosen the two pins on the
                                                    gravity weight (hexagon socket) and remove
Fig. 2.1 Lateral load                               them. Pull the cable out of the gravity weight.

                                                    To avoid fraying the steel cable (EK 31) during
Downward forces                                     cutting, you must tin the cable around the
Strong downward forces, e.g. due to sudden          cutting position with a soldering iron or
material inflow or material slide, can cause        blowtorch, or tightly wrap the cable with a
high tensile loads.                                 wire. Shorten the electrode cable with a metal
                                                    cutting saw or a cutting-off wheel by the re-
In such cases, use a rod electrode for short        quested length.
meas. distances, because a rod is usually
more stable. If, due to the length or the instal-
lation position, a cable electrode is necessary,    Carry out an adjustment. The instruction is
the electrode should not be fixed but simply        under „4.1 Adjustment“.
provided with a gravity weight to allow the
cable to more easily follow the product move-
ments. Make sure that the electrode cable
does not touch the vessel wall.
                                                                                                         22574-EN-020809




16                                                        Capacitive electrodes EK 4 … 20 mA - Compact
                  Mounting




                                                                      Fig. 2.3 Moisture

                                                                     Cable entries
                  Fig. 2.2 Shortening the electrode                  When mounting outdoors, on cooled vessels
                                                                     or in humid areas where cleaning is done, e.g.
                                                                     with steam or high pressure, the seal of the
                  Filling opening
                                                                     cable entry is very important.
                  Install the electrode such that it does not pro-
                  trude directly into a strong filling stream.
                                                                     Use cable with round cross-section conductor
                  Should such an installation location be neces-
                                                                     and tighten the cable entry. The cable entry is
                  sary, mount a suitable protective sheet in front
                                                                     suitable for cable diameters of 5 mm to 9 mm.
                  of the electrode, e.g. L 80 x 8 DIN 1028, etc.


                                                                     Metal vessel
                  Humidity from outside
                                                                     Make sure that the mechanical connection of
                  To avoid moisture ingress, the connection
                                                                     the electrode to the vessel is electrically con-
                  cables to the electrode housing of vertically
                                                                     ductive in order to ensure sufficient ground-
                  installed electrodes should be led downward
                                                                     ing.
                  directly outside the cable entry. Rain and
                  condensation water can then drain off.
                                                                     Use conductive seals such as e.g. copper,
                                                                     lead etc. Insulating measures, such as cover-
                  This is mainly valid for outdoor mounting, in
                                                                     ing the thread with Teflon tape, can interrupt
                  areas where high humidity is expected (e.g.
                                                                     the necessary electrical connection. In such a
                  from cleaning processes) or for cooled or
                                                                     case, use the earth terminal on the housing to
                  heated vessels (see fig. 2.3).
                                                                     connect the electrode to the vessel wall.
22574-EN-020809




                  Capacitive electrodes EK 4 … 20 mA - Compact                                                      17
                                                                                             Mounting


Non-conductive vessels
In non-conductive vessels, e.g. plastic tanks,
the second pole of the capacitor must be
provided separately, e.g. in the form of a
concentric tube.

When using a standard electrode, a suitable
grounding surface is necessary. Provide
therefore the largest possible grounding sur-
face, e.g. wire braiding laminated into the
vessel wall or metal foil glued to the vessel.
Connect the grounding surface to the ground
terminal on the housing.
                                                    Fig. 2.4 Cable electrode in solids
Rod electrode
                                                    With measuring probes that deliver continuous
Mount the rod electrode such that the elec-
                                                    measured values, the electrode must be in-
trode protrudes into the vessel. When mount-
                                                    stalled vertically. If installation from the top is
ing in a tube or a socket, material buildup
                                                    not possible, the electrodes can also be
which deters the measurement can form. This
                                                    mounted laterally (fig. 2.5).
is particularly the case with viscous or adhe-
sive mediums.
                                                    Under accessories in our price list, you can
                                                    find a screening tube and a closing cone or an
                                                    angled rod electrode with which the instrument
Cable electrodes in solids                          can also be laterally mounted. Determine a
Depending on the type of solid, the filling         screening tube length (L) that will not allow
method and its location, the cable electrode        product bridges to form between cable and
may „float“ in spite of the gravity weight. The     vessel wall, and that will not allow the electrode
electrode (cable) is pushed by the solid            cable to touch the vessel wall. Use a fixing
against the vessel wall or to the surface, thus     weight or a fixing insulator.
causing incorrect measured values. This
should be avoided during continuous meas-
urement.

If this happens, use a fixing weight or insulator
to secure the cable electrode (fig. 2.4)
                                                                        L
When securing the cable electrode, avoid high
tensile forces. An appropriate fixing spring
which prevents cable overload can be found
in our price list.
Lateral mounting                                      Fixing weight




                                                    Fig. 2.5 Continuous electrodes
                                                                                                          22574-EN-020809




18                                                         Capacitive electrodes EK 4 … 20 mA - Compact
                  Mounting


                  Material cone                                              The measuring probe must be installed in a
                  When installing the measuring probe in a                   way that takes the filling and emptying aper-
                  vessel, be aware that conical heaps which                  tures of the vessel into account. To compen-
                  alter the switching point can form in solid ma-            sate measurement errors caused by the
                  terial. We recommend choosing an installation              conical heap, you should install the electrode
                  location that enables the electrode to detect              at a distance of approx. d/6 from the vessel
                  the average value of the conical heap.                     wall. Make the distance to the wall as big as
                                                                             possible for solids which tend to form cor-
                                                                             nices.



                               ;;    ;;                                ;;;;;;;
                                                                       ;
                               ;;    ;;
                                                                             ;
                                                                       ;;;;;;;
                                                                       ;     ;
                               ;;    ;;   Filling                      ;     ;    Emptying
                               ;;
                  ;;;;;;;;;;;;;;;    ;;                                ;     ;
                               ;;
                  ;;;;;;;;;;;;;;;
                                     ;;;;;;;;;;;;;;;;
                                     ;;
                                     ;;;;;;;;;;;;;;;;
                                                         ;;;;;;;;;;;;;;;
                                                                       ;
                                                         ;;;;;;;;;;;;;;;
                                                                             ;;;;;;;;;;;;;;;
                                                                             ;
                                                                             ;;;;;;;;;;;;;;;
                  ;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;     ;;;;;;;;;;;;;;;
                  ;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;     ;;;;;;;;;;;;;;;
                  ;;;;;;;;;;;;;;;
                     d
                  ;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;;
                                     ;;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;
                                                            d
                                                         ;;;;;;;;;;;;;;;     ;;;;;;;;;;;;;;;
                                                                             ;;;;;;;;;;;;;;;
                  ;;;;;;;;;;;;;;;
                       ;;
                  ;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;
                                                              ;;             ;;;;;;;;;;;;;;;
                       ;;
                     6 ;;
                  ;;;;;;;;;;;;;;;
                                     ;;;;;;;;;;;;;;;;
                                     ;;;;;;;;;;;;;;;;
                                                         ;;;;;;;;;;;;;;;
                                                              ;;
                                                            6 ;;
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                       ;;            ;;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;
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                       ;;            ;;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;
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                       ;;
                  ;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;
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                       ;;
                  ;;;;;;;;;;;;;;;
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                       ;;
                  ;;;;;;;;;;;;;;;
                       ;;
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                  ;;;;;;;;;;;;;;;
                       ;;            ;;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;
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                  ;;;;;;;;;;;;;;;
                       ;;
                  ;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;;
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                  ;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;     ;;;;;;;;;;;;;;;
                  ;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;     ;;;;;;;;;;;;;;;
                  ;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;     ;;;;;;;;;;;;;;;
                  ;;;;;;;;;;;;;;;
                  ;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;;
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                                                         ;;;;;;;;;;;;;;;     ;;;;;;;;;;;;;;;
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                  ;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;     ;;;;;;;;;;;;;;;
                  ;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;     ;;;;;;;;;;;;;;;
                  ;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;     ;;;;;;;;;;;;;;;
                  ;;;;;;;;;;;;;;;
                  ;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;;
                                     ;;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;
                                                         ;;;;;;;;;;;;;;;     ;;;;;;;;;;;;;;;
                                                                             ;;;;;;;;;;;;;;;
                  ;;;;;;;;;;;;;;; d ;;;;;;;;;;;;;;;;
                  ;;;;;;;;;;;;;;;
                                                         ;;;;;;;;;;;;;;; d ;;;;;;;;;;;;;;;
                                                         ;;;;;;;;;;;;;;;
                                     ;;;;;;;;;;;;;;;;                        ;;;;;;;;;;;;;;;
                  ;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;     ;;;;;;;;;;;;;;;
                  ;;;;;;;;;;;;;;;
                  ;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;;
                                     ;;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;
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                  ;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;     ;;;;;;;;;;;;;;;
                  ;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;     ;;;;;;;;;;;;;;;
                  ;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;     ;;;;;;;;;;;;;;;
                  ;;;;;;;;;;;;;;;
                  ;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;;
                                     ;;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;
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                  ;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;     ;;;;;;;;;;;;;;;
                  ;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;     ;;;;;;;;;;;;;;;
                  ;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;     ;;;;;;;;;;;;;;;
                  ;;;;;;;;;;;;;;;
                  ;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;;
                                     ;;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;
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                  ;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;     ;;;;;;;;;;;;;;;
                               ;;;;;;;;
                  ;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;;    ;;;;;;;;;;;;;;;     ;;;;;;;;;;;;;;;


                  Fig. 2.6 Material cone, filling and emptying centered



                                               Filling                               Emptying
                                                                                                                        3
                                                                                                     10
                                                                                                     d




                                                                                                                              1
                                                                                                d




                                                                                                                              2




                                                                                                    1 Emptying
                                                                                                    2 Filling opening
                                                                                                    3 Capacitive
                  Fig. 2.7 Material cone, filling centered, emptying laterally                        electrode
22574-EN-020809




                  Capacitive electrodes EK 4 … 20 mA - Compact                                                              19
                                                                                                   Electrical connection


3 Electrical connection                                   3.2 Wiring plan

3.1 Connection instructions                               Note
                                                          The oscillator is independent of the electrode
Note                                                      and can be exchanged on site.
Switch off the power supply before starting
connection work.
                                                                                       +
Connect the supply voltage according to the                                                                    4 … 20 mA
                                                                                       –
following connection diagrams.

A multimeter can be connected to terminals 3
and 4 for setup. This connection is not suitable
for an indicating instrument.


Note
If strong electromagnetic interference is ex-
pected, we recommend using screened ca-
ble. The screening of the cable should only be
earthed on one end, i.e. the sensor end (elec-
trode).
                                                                                                       0
                                                                                                   8       2
Always connect the electrode to vessel                                         +   - + -
                                                                                                   6       4
                                                                               1 2 3 4
ground (PA). For this purpose there is a termi-                                              -                  +
nal on the side of the housing. This connection
is also used to supply the ground reference                                              mA
potential as well as to drain off electrostatic                                    U = 12 … 36 V
charges.




     + - + -        Terminals
                    Sensor
     1 2 3 4

                                                 analogue/digital indicating
                   with bridge:                  instrument
                   12 …36 V
                   without bridge:
                   13 … 36 V
                                                                                                 PLC
                                                                                      –
                                                                                                                           22574-EN-020809




                     UK                  UA
                                                                 UH
                                     4 … 20 mA                                       +
                                     U = 12 … 36 V                                                 Ri < 250




20                                                                Capacitive electrodes EK 4 … 20 mA - Compact
                  Electrical connection


                  Qualified personnel
                  Instruments which are operated in Ex areas
                  must only be connected by qualified person-
                  nel. They have to note the installation regula-
                  tions and the attached EC type approval
                  certificates and conformity certificates.

                  If the capacitive electrodes are to be mounted
                  on vessels which must be protected against
                  the danger of ignition by lightning (acc. to
                  TRbF 100 no. 8, para.1), they have to be
                  equipped with the external overvoltage pro-
                  tection unit type B 62-36 G or the internal
                  overvoltage protection unit type CB 2-36.
22574-EN-020809




                  Capacitive electrodes EK 4 … 20 mA - Compact      21
22




                                                                                                                                                                                                                                  Vessel with cathodic corrosion protection
                                                 a) Capacitive electrodes with integrated
                                                 overvoltage protection unit type CB 2-36
                                                                                                              (Ex) area Zone1                                           Non (Ex) area
                                                           Overvoltage
                                                           protection unit
                                                           mounted to
                                                           oscillator        CB     2
                                                                                    1
                                                                             2-36
                                                                                                  Li, Ci of the oscillator with overvoltage
                                                                             CAP
                                                           Oscillator        E32(H)EX             protection unit
                                                                                                  Li = 0.27 mH                                                                 Control room
                                                                                                  Ci = 8.5 nF                                                                  optionally:
                                                                                                                                                                               Overvoltage
                                                                                                                                          Schirm
                                                                                                 External ground terminal                                                      protection insert
                                                                                                                                                                                                       Signal
                                                                                                                                                                                  Type B62-36G
                                                                                                                                                                                  E2                   condit-
                                                                                    Vessel        Internal ground terminal
                                                                                                                                                                                               A2
                                                                                                                                                                                  E1           A1      ioning
                                                                                    Zone 0                                                                                        Li=0.15 mH
                                                                                                                                                                                  Ci=2.5 nF            instru-
                                                                                                                                      A                                                                ment
                                                                                                                                                                                                       or
                                                                                          Cathodic tank protection                                                                                     safety
                                                                                          2 … 24 V (object voltage)                                                                                    bar-
                                                                                                                                                                                                       rier

                                                 b)Capacitive electrodes with external
                                                                                                                                                                            A suitable cable, if necessary with metal cover or
                                                   overvoltage protection unit                                                                                          A   screen, must be used between control room and
                                                                                                                                                                            overvoltage protection system. Metal cover or
Capacitive electrodes EK 4 … 20 mA - Compact




                                                                                                               Overvoltage protection unit                                  screen - if necessary - should only be connected to
                                                                             CAP                                                                                            the electrode side of the overvoltage protection
                                                                             E32 2                                                                                          system. The cable must have an outer insulation.
                                                        Oscillator                                                     A2 Typ     E2
                                                                             (H)Ex 1                                   A1 B62-36G E1                                        Test voltage of cable A: • 500 V AC
                                                        Li=0.12 mH                                                       Li=0.15 mH
                                                        Ci=6 nF                                                          Ci=2.5 nF

                                                                                                     B
                                                                                                                                                                            A suitable cable with metal cover, screen or a
                                                                                                     Screen                                                             B   suitable cable in a protective metal tube must be
                                                                                                     Insulated cable                                                        used between overvoltage protection system and
                                                                                                                                                                            capacitive electrode (metal cover or protective




                                                                                                                                                                                                                                                                              Electrical connection
                                                                                                     min. 4 mm2
                                                                                    Vessel                                                                                  tube must not be earthed)
                                                                                    Zone 0                                                Overvoltage arrester in           Test voltage of cable B: • 1500 V AC
                                                                                                         External ground terminal         metal housing or in plastic
                                                                                                                                          housing must be installed
                                                                                                         Internal ground terminal         earth-free

                                                                                        Cathodic tank protection
                                                                                        2 … 24 V (object voltage)




                                               22574-EN-020809
                                               22574-EN-020809




                                                                                                                                                                                                                                  Vessel without cathodic corrosion protection
Capacitive electrodes EK 4 … 20 mA - Compact




                                                                                                                                                                                                                                                                                 Electrical connection
                                                 a) Capacitive electrodes with integrated
                                                 overvoltage protection unit type CB 2-36
                                                                                                               (Ex) area Zone1                                      Non (Ex) area


                                                           Overvoltage        CB     2
                                                           protection unit    2-36   1
                                                           mounted on
                                                           oscillator                                 Li, Ci of the oscillator with overvoltage
                                                                              CAP
                                                                              E32(H)EX
                                                                                                      protection unit
                                                                                                      Li = 0.27 mH                                                                  Control room
                                                                                                      Ci = 8.5 nF                                                                   optionally:
                                                           Oscillator                                                                                                               Overvoltage
                                                                                                             External ground terminal           Screen                              protection insert
                                                                                                                                                                                                              Signal
                                                                                                                                                                                       Typ B62-36G
                                                                                                                                                                                                              condit-
                                                                                         Vessel               Internal ground terminal                                                 E2            A2
                                                                                                                                                                                       E1            A1       ioning
                                                                                         Zone 0                                                                                        Li=0.15 mH
                                                                                                          to the potential equalisa-                                                   Ci=2.5 nF
                                                                                                                                                                                                              instru-
                                                                                                          tion line                                                                                           ment
                                                                                                                                          A
                                                                                                                                                                                                              or
                                                                                                       * optional                                                                                             safety
                                                                                                       Connect screen only on one                                                                             bar-
                                                                                                       cable end to ground or PA                                            *                                 rier
                                                                                                                                                                            **
                                                 b)Capacitive electrodes with external
                                                 overvoltage protection unit                                                                                                     A suitable cable, if necessary with metal
                                                                                                                                                                        A        cover or screen, must be used between
                                                                                                                                                                                 control room and overvoltage protection
                                                                                                                                                                                 system. Metal cover or screen - if necessary
                                                                                                                   Overvoltage protection insert
                                                        Oscillator                                                                                                               - should only be connected with one cable
                                                                              CAP
                                                        Li=0.12 mH                                                            Typ                                                end to ground or PA.
                                                                              E32 2                                         A2
                                                                                                                               B62-36G E2
                                                        Ci=6 nF                     1                                       A1 Li=0.15 mH E1                                     Test voltage of cable A: • 500 V AC
                                                                              (H)Ex
                                                                                                                              Ci=2.5 nF


                                                                                                      B                                                                          A suitable cable with metal cover, screen or a
                                                   External ground terminal
                                                                                                          Screen                                             **         B        suitable cable in a protective metal tube must
                                                                                                                                                                                 be used between overvoltage protection
                                                   Internal ground terminal                                                                                                      system and capacitive electrode (metal cover
                                                                                                          Insulated cable                                                        or protective tube must be connected to the
                                                                                     Vessel               min. 4 mm2                                                             potential equalisation)
                                                                                     Zone 0            to the potential equali-      Overvoltage arrester type                   Test voltage of cable B: • 1500 V AC
                                                                                                       sation line                   B62-36 G in metal or plastic
                                                                                                                                     housing
                                                                                                  ** optional
                                                                                                  Connect screen only on one
                                                                                                  cable end to ground or PA
23
                                                                                                     Setup


4 Setup
4.1 General adjustment                                    PC with adjustment program VVO1)
                                                          The capacitive electrodes, in conjunction with
In the setup procedure, the electrode must be             oscillator CAP E 32 H Ex, can be very conven-
adjusted to the medium which will later be                iently operated with the adjustment program
measured.                                                 VVO (VEGA Visual Operating). Additional
In certain cases, a dry adjustment is also                functions are available beside the basic sen-
possible.                                                 sor functions.

The electrode can be adjusted in three differ-            For this, you require an interface adapter
ent ways:                                                 VEGACONNECT 2 which you can connect
• with the integrated oscillator                          directly to any position on the signal cable or
• with the adjustment software VEGA Visual                directly to the sensor.
  Operating (VVO from version 2.30)
• with a HART® handheld                                   System requirements:
                                                          - IBM compatible PC with a free serial port.
                                                            We recommend a PC with Pentium proces-
CAP E 32 Ex                                                 sor with a clock frequency of
Adjustment        - directly on the oscillator.             100 MHz.
                                                          - Memory: 16 MB
CAP E 32 H Ex                                             - Software requirements: Windows 95
Adjustment    - directly on the oscillator
              - via PC with the adjustment
                program VVO1)                             HART® handheld
              - via HART® handheld                        The capacitive electrodes EK with oscillator
                                                          CAP E32 H Ex are HART® protocol capable
                                                          and can be adjusted with a HART® handheld.
Oscillator                                                All relevant sensor functions can be executed
The capacitive electrodes EK can be adjusted              with the HART® standard menus. A manufac-
directly on the oscillators CAP E32 Ex and                turer-specific DDD (Data-Device-Description)
CAP E32 H Ex.                                             is not necessary.
All basic sensor functions can be executed via
the two keys and the rotary switch.




1) If you want to adjust a sensor with the PC, you have
   to connect the PC cables to the signal cable outside
                                                                                                               22574-EN-020809




   the Ex zone.
   The intrinsic safety must not be impaired by this
   connection. Use a suitable interface converter, e.g.
   VEGACONNECT 2


24                                                              Capacitive electrodes EK 4 … 20 mA - Compact
                  Setup


                  4.2 Adjustment - Oscillators                             Function description
                      CAP E32 Ex and CAP E32 H Ex
                                                                           0 Operate
                                                      1       2   3        Basic setting
                                                                           While operating, the instrument should always
                                                      0
                                                  8       2
                                                                           be in this position. The actual measured value
                                                  6       4
                                    1 2 3 4
                                              -               +            is transmitted in the Operate mode. The plus
                                                                           and minus key are not in operation.

                                                                           1 Min. adjustment
                                                                           This function is used to carry out the min.
                                                                           adjustment. Lower the product to min. level
                                                                           (0 % level).
                                                                           Push the plus and minus keys simultaneously
                                                                           to set the current value for the actual level to
                                                                           4 mA.
                                                                           If you want to assign a certain current value to
                  1 Minus key
                                                  + - + -                  a known level, you can change the current
                  2 Rotary switch                 1 2 3 4                  with the plus and minus keys. Each push of
                  3 Plus key
                                                                           the key changes the current value by a 10 µA
                                                                           increment. If you hold the key pushed, the
                                                                      mA
                                                                           value changes with rising speed.
                                                                           Example: If you know that your vessel is filled
                                                                           to 10 %, then you can enter a value of 5.6 mA
                                                  U = 12 … 36 V
                                                                           under the min. adjustment.
                  Rotary switch (2)                                                 20 mA - 4 mA = 16 mA
                  With the rotary switch (10 steps) you select                      16 mA * 10% = 1.6 mA
                  the appropriate mode.                                             1.6 mA + 4 mA = 5.6 mA
                  As soon as you continue turning the rotary
                  switch, the modified value will be saved.                We recommend that you connect an ammeter.
                                                                           See 3.2 Electrical connection. By doing this,
                  0   Operate                                              you can monitor the current value while you
                  1   Min. adjustment                                      are modifying it. If you hold the key pushed,
                  2   Max. adjustment                                      the value changes automatically and with
                  3   Integration time                                     rising speed. The difference between min. and
                  4   Reverse characteristics                              max. adjustment should be at least 20% or 3.2
                  5   Linearisation                                        mA.
                  6   Sensor optimisation
                  7   Simulation current                                           (+/-)   set 4 mA
                  8   Reset                                                        (+)     increase current
                  9   Offset correction                                            (-)     reduce current



                  Plus and minus keys (3 and 1)                            2 Max. adjustment
                  With the + and - keys you can modify the                 This function is used to carry out the max.
                  values or choose from several options.                   adjustment. Fill the product to max. level (100
                  If you push both keys simultaneously, the                % level). Push the plus and minus keys simul-
                  value of the respectively selected function will         taneously. By doing this, you can set the cur-
                  be reset to default (except min./max. adjust-            rent value for the actual level to 20 mA.
22574-EN-020809




                  ment).




                  Capacitive electrodes EK 4 … 20 mA - Compact                                                           25
                                                                                              Setup


If you want to assign a certain current value to   4 Reverse characteristics
a known level, you can modify the current with     With this function you can reverse the charac-
the plus and minus keys. Each push of the          teristics of the current output. The reverse is
key changes the current value by a 10 µA           also shown on the ammeter.
increment.
If you hold the key pushed, the values                    (+/-)   4 ... 20 mA
changes with rising speed.                                (-)     4 ... 20 mA
Example: If you know that your vessel is filled           (+)     20 ... 4 mA
up to 90 % and will be completely full at
100 %, then you can enter under max. adjust-
ment a value of 18.4 mA.                           5 Linearisation
        20 mA - 4 mA = 16 mA                       With this function you can activate the saved
        16 mA * 90% = 14.4 mA                      linearisation curve. As a standard feature, the
        14.4 mA + 4 mA = 18.4 mA                   curve for a cylindrical tank is contained in
                                                   memory. With CAP E 32 H you can enter other
We recommend that you connect an ammeter.          linearisation curves via VVO. In this case,
See 3.2 Electrical connection. By doing this,      presetting the oscillator is not necessary.
you can monitor the current value during
modification. If you hold the key pushed, the             (+/-)   Linearisation Off
value changes automatically and with rising               (+)     Linearisation ON
speed. The difference between min. and max.               (-)     Linearisation Off
adjustment should be at least 20% or 3.2 mA.

        (+/-)   set 20 mA                          6 Sensor optimisation
        (+)     increase current                   Mode 1 = Phase angle 90°
        (-)     reduce current                     Mode 1 is a pure capacitance measurement,
                                                   the ohmic conductance is not taken into ac-
                                                   count in the measuring result. t
3 Integration time                                 Application:
If you want to set the integration time (damp-     - standard setting
ing), you have to set the rotary switch to posi-   - non-conductive liquids up to approx.
tion 3. With the plus and minus keys you can         50 µS
double or halve the value of the integration       - compensation of conductance changes in
time step by step. As a standard feature, an         liquids
integration time of 0.5 seconds is set. Count      - generally with partly insulated electrodes in
how often you push the key so that you can           liquids
set the time correctly. In case of doubt, you      - non-conductive solids without moisture
can reset the integration time to the preset         content
value of 0.5 s by pushing both keys simulta-       - with insufficient product grounding
neously. Then you repeat the setting. After the    - with electrodes in conjunction with a concen-
set integration time has expired,                    tric tube
63 % of the measured value change is trans-        - in non-conductive vessels with exterior
mitted to the output.                                ground surface
The following integration times can be selected
on the oscillator: 0.5; 1; 2; 4; 8; 16; 32; 64;
128; 256 (s)

       (+/-) 0.5 s
       (+)     increase time
                                                                                                        22574-EN-020809




       (-)     reduce time
Example: To set an integration time of 8 sec-
onds, you have to push the „+“ key 4 times.



26                                                       Capacitive electrodes EK 4 … 20 mA - Compact
                  Setup


                  Mode 2 = Phase angle 45°                            Default
                  The capacitance and the ohmic conductance           0 Operate                 ---
                  are measured separately, the capacitance            1 Min. adjustment         4 mA at 0 pF
                  value is corrected by calculating it with the       2 Max. adjustment         20 mA at 3000 pF
                  ohmic conductance, so that measurement              3 Integration time        0.5 s
                  errors caused by conductive buildup or vary-        4 Reverse charact.        4 ... 20 mA
                  ing product moisture are compensated.               5 Linearisation           Off
                  Application:                                        6 Sensor optimisation     Mode 1 (90°)
                  - highly conductive products                        7 Simulation current      Off
                  - adhesive, conductive products                     8 Reset                   ---
                  - solids with fluctuating moisture content          9 Offset correction       already saved values
                                                                                                remain
                  For applications in conductive, viscous liquids,
                  you should use a suitable electrode of type EK
                  24.                                                 9 Offset correction
                         (+/-)    Mode 1 (90°)                        This function is necessary if an adjustment
                         (–)      Mode 1 (90°)                        should be carried out in m. This is only possi-
                         (+)      Mode 2 (45°)                        ble in conjunction with the CAP E 32 H Ex
                                                                      oscillator. With this function, the initial capaci-
                                                                      tance in the electronics is saved. A prerequi-
                  7 Simulation current                                site is that the electrode is mounted into the
                  With this function you can simulate the level.      vessel and that it is completely uncovered by
                  As soon as the rotary switch is set to position     the medium.
                  7, the simulation will be active. The current
                  value of the instantaneous level is used as the     For electrodes with concentric tube, this func-
                  initial simulation value. With the plus and minus   tions is already carried out at VEGA as the
                  key you can modify the current value between        vessel does not influence the measurement.
                  3.8 mA and 22 mA. Each push of the key              The offset correction must only be repeated if
                  changes the current value by a 10 µA incre-         the oscillator is exchanged.
                  ment.
                  If you hold the key pushed, the value changes               (+/–)    Initial capacitance is saved
                  automatically and with rising speed.

                          (+)     increase current
                          (-)     reduce current


                  8 Reset
                  This function sets all values to default.
                  Take note that also the adjustment will be
                  deleted. Tag number, measurement loop des-
                  ignation etc. from the HART® or VVO adjust-
                  ment, however remain unchanged.

                          (+/-)   Default
22574-EN-020809




                  Capacitive electrodes EK 4 … 20 mA - Compact                                                          27
                                                                                               Setup

4.3 Adjustment with VVO                             VVO recognises automatically the type of the
                                                    connected sensor and immediately after-
If oscillator CAP E 32 H Ex is installed, the       wards indicates with which sensor a connec-
electrode can also be adjusted via a PC with        tion exists.
adjustment software VVO (from version 2.30).
                                                    If you get no sensor connection, please check
                                                    the following:
PC mit VVO                   + - + -                - the supply voltage must be at least 12 V.
                              1 2 3 4               - If VEGACONNECT 2 is connected directly
                                                       to the sensor cable, the load resistance
             VEGACONNECT 2                             must be 250 ... 350 Ohm.
                                         mA         - You have to use a VEGACONNECT 2.
                                                       Older versions of VEGACONNECT are not
                                   approx.             compatible.
                                   250 Ohm


Note                                                For further information, see the operating
If the resistance of the supply voltage is less     instructions manual of the adjustment program
than 250 Ohm, a resistance must be con-             VEGA Visual Operating (VVO).
nected to the signal/connection cable during
adjustment. The digital adjustment and com-
munication signals would otherwise be short-
circuited by insufficient resistance, e.g. of the
supply current source or the processing
system, resulting in possible failure of sensor
communication. The easiest way is to connect
the necessary adjustment resistance in paral-
lel to the connection socket of the HART®
handheld (see 4.4 Adjustment with the HART®
handheld).

• Switch on the power supply of the con-
  nected sensor.
• Start the adjustment software VVO (VEGA
  Visual Operating) on your PC.
• In the initial window you choose with the
  arrow keys or the mouse the item Planning
  and click to OK.
  Planning should only be selected if you are
  authorised to modify instrument parameters.
  Otherwise select Operator or Maintenance.
  In the window “User identification” you are
  asked for the name and the password.
• For setup (Planning) you enter under name:
  VEGA and under password also: VEGA.
  You can use capital or small letters.
                                                                                                         22574-EN-020809




28                                                        Capacitive electrodes EK 4 … 20 mA - Compact
                  Setup


                  4.4 Adjustment with HART®                         Burst mode
                      handheld                                      Normally the sensor signals the measured
                                                                    values to the processing unit only on request.
                  The capacitive electrodes EK with oscillator      If you switch on the burst mode, the sensor
                  CAP E32 H Ex are HART® protocol capable           signals the measured value without being
                  and can be adjusted with a HART® handheld.        requested.


                    HART® handheld
                                                + - + -
                                                 1 2 3 4            Note
                                                                    If the resistance of the power supply is less
                                                                    than 250 Ohm, a resistor must be connected
                                                                    to the signal/connection cable during adjust-
                                                            mA      ment. Otherwise the adjustment and communi-
                                                       250 Ohm
                                                                    cation signals would be short-circuited by
                                                                    insufficient resistance, e.g. of the supply cur-
                                                                    rent source or the processing system, result-
                  All relevant sensor functions can be executed     ing in possible failure of sensor
                  with the HART® standard menus. A manufac-         communication. The easiest way is to connect
                  turer-specific DDD (Data-Device-Description)      the adjustment resistance in parallel to the
                  is not necessary.                                 connection socket of the HART® handheld
                  Connect the HART® handheld to the sensor          (see fig. 1, page 36).
                  signal cable after you have connected the
                  sensor to power supply.
                                                                    Connection to a VEGA signal conditioning
                                                                    instrument
                  Multidrop mode                                    (fig. 3 on the next page)
                  The multidrop mode can be selected with the       If you operate a HART® capable sensor on a
                  HART® handheld.                                   VEGA signal conditioning instrument, you
                  With this mode, several HART® sensors can         have to a connect a resistance (acc. to the
                  be connected to a single two-wire cable.          following table) to the sensor connection on
                  Beside the 4 … 20 mA signal, the sensor also      the signal conditioning instrument during the
                  delivers a digital (HART®) level signal.          HART® adjustment.
                  • If you enter address 0 (factory setting), the
                                                                    VEGA signal conditioning instr.   Rx
                    sensor consumes a level-dependent
                    4 … 20 mA current and delivers a digital        VEGAMET 513, 514, 515, 602
                    (HART®) level signal. It is also possible to    VEGATRENN 544
                    connect e.g. an indicating instrument           VEGATOR 521…527                   50 … 100 Ohm
                    (4 … 20 mA) to this cable.
                  • If you enter an address between 1 and 15,       VEGAMET 614                       no additional
                    the sensor consumes a permanent 4 mA            VEGADIS 371                       resistance
                    current and delivers a digital (HART®) level                                      necessary
                    signal.
                                                                    VEGAMET 601                       200 … 250 Ohm

                                                                    VEGASEL 643                       150 … 200 Ohm

                                                                    VEGAMET 513 S4, 514 S4
                                                                    515 S4                            100 … 150 Ohm
22574-EN-020809




                  Capacitive electrodes EK 4 … 20 mA - Compact                                                        29
                                                                                Setup

PLC with Ri < 250 Ohm


                                          +

                                                           PLC
                             250          –
                                                           Ri < 250




                                                                                 Fig. 1



PLC with Ri > 250 Ohm


                                              +


                                                          PLC
                                              –
                                                           Ri > 250




                                                                                  Fig. 2



VEGAMET signal conditioning instruments
or VEGALOG
                                                      VEGAMET         VEGALOG

                                                  +


                               250 Ohm
                                                  –
                                                                                           22574-EN-020809




                                                                                Fig. 3



30                                        Capacitive electrodes EK 4 … 20 mA - Compact
                  Setup


                  Adjustment steps                                  In a further safety enquiry you are asked to
                                                                    switch the system from manual to automatic
                  On the following pages you will see the menu      operation. Confirm with „OK“.
                  schematic of the HART® handheld in conjunc-        Generic: SENSOR
                  tion with capacitive electrodes.
                                                                             - WARNING-
                  The most important adjustment steps are
                  marked in the menu schematic with the letters      Return control loop to
                                                                     automatic control.
                  A … D.
                                                                                              OK
                                                     ®
                  General information on the HART handheld:

                  If you have entered or modified parameters,       With „HOME“ you return to the initial menu.
                  you have to push the „ENTER“ key. The ad-
                  justment is saved in the handheld, but not in      Generic: SENSOR
                                                                      1 PV    LRV
                  the sensor itself.                                  2 PV    URV



                   Generic: SENSOR            4.1
                   PV LRV                    (5.1)                   HELP           HOME
                       0.000 m
                    10.000



                  HELP DEL ABORT ENTER
                  Empty adjustment without
                  medium




                  After you have pushed „ENTER“, you have to
                  push „SEND“ to transfer the settings to the
                  sensor.

                   Generic: SENSOR
                    1 PV    LRV
                    2 PV    URV




                   HELP SEND      HOME


                  After pushing „SEND“, a warning is displayed.
                  If you push „OK“, the setting is transferred to
                  the sensor.


                   Generic: SENSOR
                          - WARNING-
                   Pressing ”OK“ will
                   change device output.

                   Put loop in manual

                                  ABORT OK
22574-EN-020809




                  Capacitive electrodes EK 4 … 20 mA - Compact                                                     31
                                                                                                                  Setup


HART® menu schematic
                                 Set-up the sensor in the sequence of the
                                 figures A, B, C and D (adjustment without                                           1.1
                                                                                       Generic: Sensor
Switch on:                       medium).                                              Process variables
                                 In case of adjustment with medium, set-up               1 Snsr      2,56 m
     Hart Communicator           the sensor in the sequence A1, B1, C and                2 AI % rnge
                                 D.                                                      3 AO1
 Self Test
   in Progress
                                       Generic: Sensor                1
                                                                                       HELP    SAVE HOME
 Firmware Rev: F2.2                    Device setup
 Module Rev: 3.6                        1 Process variables
    01992-96 FRSI                       2 Diag/Service
                                        3 Basic setup
                                        4 Detailed setup
                 after approx.          5 Review
                 20 s                         SAVE HOME

Generic: Sensor
Online(Generic)
 1 Device setup
 2 PV                                  Generic: Sensor                2
 3 PV AO                               PV
 4 PV LRV                                2,56 m
 5 URV
HELP SAVE


                                       HELP                  EXIT

                                       Generic: Sensor                3
                                       AO1
                                        16.952 mA




                                       HELP                  EXIT




                                                                             Generic: Sensor               4.1

                                   Generic: Sensor                4   A      PV LRV
                                                                                  0.000 m
                                                                                 10.000
                                                                                                          (5.1)

                                    1 PV LRV
                                    2 URV
Important and
necessary menu                                                               HELP DEL     ESC ENTER
windows                                                                      Empty adjustment without
                                   HELP SEND HOME                            medium

                                                                             Generic: Sensor               4.2


Less important
                                                                      B      PV URV
                                                                                100.000 m
                                                                                 90.300
                                                                                                          (5.2)


menu windows                                                  5
                                 Generic: Sensor
                                  1 PV LRV
                                  2 URV
                                                                             HELP DEL       ESC   ENTER
                                                                                                                           22574-EN-020809




                                                                             Full adjust-
                                                                             ment without
                                                                             medium
Not required, unimportant
or blocked menu windows           HELP SEND HOME
                                                                                       continue like under A
                                 continue under figure 4                               figure 4.1(5.1)



32                                                                    Capacitive electrodes EK 4 … 20 mA - Compact
                  Setup


                                                                        Generic: Sensor           1.2.2
                                                                        Choose analog output
                                                   1.1.1                level                           Individual current values for
                     Generic: Sensor                                      1 4 mA
                     PV                                                                                 test purposes (simulation of
                                                                          2 20 mA                       measured values)
                      0,2 m                                               3 Other
                                                            Confirm
                                                            safety        4 End
                                                            enquiry                   ABORT ENTER
                                                                                                  1.2.3
                                                                        Generic: Sensor
                                                                                                                A1        Empty and full
                     HELP
                     Generic: Sensor
                     PV % rnge
                      8.945 %
                                          EXIT
                                                   1.1.2
                                                                        Calibration
                                                                          1 Apply values
                                                                          2 Enter values
                                                                                                                B1
                                                                                                                   }      adjustment
                                                                                                                          with medium
                                                                                                                          (see next page)



                                                                        HELP   SAVE HOME

                     HELP                 EXIT                                        Generic: Sensor               1.3.1
                     Generic: Sensor
                     AO1
                                                   1.1.3                       D      Tag
                                                                                        Sensor
                                                                                        Sensor
                                                                                                                          new entered meas-
                                                                                                                          uring loop designa-
                      5.952 mA                                                                                            tion to be confirmed
                                                                                                                          with ENTER and
                                                                                                                          SEND
                                                                                      HELP    DEL    ESC    ENTER
                     HELP                 EXIT                                        Generic: Sensor               1.3.2
                                                                               C      PV Snsr unit
                                                                                      m
                                                                                       m
                                                                                       bbl
                                                                                       in
                  Generic: Sensor            1.2                                       cm
                  Diag/Service                                                                      ESC     ENTER
                   1 Test device
                   2 Loop test                                                        Generic. Sensor               1.3.3
                                                                                      Range values

                                                                                                                            }
                   3 Calibration                                                                                                 see next
                   4 D/A trim                                                          1 PV LRV
                                                                                       2 URV                                     page
                          SAVE   HOME        blocked menu. The follow-                 3 PV LSL
                                             ing window is displayed but               4 USL
                                             not supported by the
                                             sensor. Saving of adjust-                HELP           HOME
                                             ments carried out here, is                                             1.3.4
                                                                                      Generic: Sensor
                                             hence not possible
                                                                                      Device information
                                                                                       1 Distributor
                                                                                       2 Model       Generic

                  Generic: Sensor
                  Basic setup
                                             1.3
                                                                                       3 Dev id
                                                                                       4 Tag
                                                                                       5 Date
                                                                                      HELP SAVE HOME
                                                                                                     10/01/97
                                                                                                                          }     see next
                                                                                                                                page

                   1 Tag                                                               6 Write protect None
                   2 PV Unit                                                           7 Descriptor
                   3 Range values                                                      8 Message
                   4 Device information
                   5 PV Xfer fnctn                                                     9 PV Snsr s/n
                                                      Transmission function
                  HELP SAVE HOME                                                         Final asmbly num
                                                      (linear)
                                                                                         Revision’s
                   6 PV Damping

                                                                                      Generic: Sensor               1.3.6
                                                                                      PV Damp
                                                                                          1.000 s
                                                                                          2 .000 s



                                                                                      HELP    DEL    ESC    ENTER




                  Generic: Sensor            1.5                                      Generic: Sensor               1.4
                  Review                                                              Detailed setup
                   Model                                                               1 Sensors
                     Generic                                                           2 Signal condition
                                                                                                                            }   see next
22574-EN-020809




                                                                                       3 Output condition                       page
                                                                                       4 Device information

                  HELP    PREV   NEXT EXIT                                                   SAVE    HOME




                  Capacitive electrodes EK 4 … 20 mA - Compact                                                                              33
                                                                                                                                 Setup


HART® menu schematic (continuation)
                                                                                                          Empty adjustment with
                                                                                                          medium


                          1.2.3                           Generic: Sensor
                                                                                  1.2.3.1
                                                                                             A1           Generic: Sensor
                                                                                                          Apply new 4 mA input
Generic: Sensor                                           Set the:
Calibration                                   Confirm      1 4 mA
 1 Apply values                     1.2.3.1   safety       2 20 mA
 2 Enter values                               enquiry      3 Exit
                                                                                                                            ABORT OK
                                                                            ABORTENTER
HELP SAVE     HOME                                                                                        Generic: Sensor
                                    Generic: Sensor                 1.2.3.2                               Apply new 20 mA input
                                    Enter values
                                     1 PV LRV
                                     2 URV
                                                                        as display 4.1
                                                                                             B1
                                                                        as display 4.2
                                     3 PV USL
                                     4 PV LSL                           } Indication of sensor
                                                                          meas. range limits                                 ABBR. OK
                                    HELP      SEND HOME                                                           Full adjustment with
                                                                                              1.3.3.1             medium
                           1.3.3                                    Generic: Sensor
Generic: Sensor                                                     PV LRV
Range values                                                           0.000 mbar
 1 PV LRV                                                              10.000
 2 PV URV
 3 PV LSL
 4 USL
                                                    sensor
                                    } Indication ofrange limits
                                      measuring                     HELP DEL      ESC       ENTER
HELP          HOME                                                  Generic: Sensor                     1.3.3.2
                                                                    PV URV
                  Menu field with broken line:                         100.000 m
                  Repetition from previous                            90.300
                  page


                            1.3.4                                   HELP DEL        ESC     ENTER
Generic: Sensor
Device information
 1 Distributor                      unknown (Unknown Enumerator)
 2 Model Generic                      General
 3 Dev id                               (1.3.4.3) Indication of the sensor serial number
 4 Tag                                      (1.3.4.4) Measurement loop designation as under 1.3.1
 5 Date 01/01/97                               (1.3.4.5) Date
HELP SAVE HOME
 6 Write protect None                            None
 7 Descriptor                                Individual text
 8 Message                                Individual text
 9 PV Snsr s/n                        Indication of the sensor serial number (as menu window 1.3.4.3)
   Final asmbly num
   Revision’s
                                                    Generic: Sensor                1.4.1
                                                    Sensors
                                                     1 PV                                   Measured value
                             1.4                     2 PV Snsr unit                          Change unit
Generic: Sensor                                      3 Sensor information                     Info on lower and upper meas.
Detailed setup                                                                                range limit as well as the min.
 1 Sensors                                                                                    span (also sensor characteristics
 2 Signal condition                                 HELP SAVE       HOME                      values)
 3 Output condition
 4 Device information                               Generic: Sensor                1.4.2
                                                    Signal condition
       SAVE   HOME                                    1 Snsr Damp 1.000 s              Adjustment of the integration time
                                                      2 URV                             Adjustment of zero and span
                                                      3 AI LRV                           Adjustment of zero and span
                          like menu 1.3.4             4 Xfer fnctn Linear                  linear
                                                      5 AI % rnge                             Level indication in % of the adjusted
                                                    HELP SAVE HOME                            span
                                                     Generic: Sensor               1.4.3
                                                     Output condition
                                                      1 Analog output
                                                      2 HART output
                                                                                                                                         22574-EN-020809




                                                             SAVE   HOME




34                                                                             Capacitive electrodes EK 4 … 20 mA - Compact
                  Setup




                                      1.2.3.1.1                  1.2.3.1.1.1
                  Generic: Sensor               Generic: Sensor
                  Current applied               Set the:
                  process value: 10.945          1 4 mA
                  mbar                           2 20 mA
                    1 Set as 4 mA value          3 EXIT
                    2 Read new value
                    3 Leave as found
                                 ABORT ENTER                  ABORT ENTER

                  Generic: Sensor                  Generic: Sensor
                  Current applied                  Set the:
                  prosess value :85.281             1 4 mA
                  mbar                              2 20 mA
                   1 Set as 20 mA value             3 Exit
                   2 Read new value
                   3 Leave as found
                                ABORT ENTER                        ABORT ENTER
                                      1.2.3.1.2                        1.2.3.1.2.1


                                                                            1.4.3.1.2
                                                      Generic: Sensor
                                                      AO Alrm typ
                                                      Hi
                                                                                            High:   Current output goes to < 3,6 mA
                                                                                                    in case of failure

                                                                             EXIT

                                         1.4.3.1                        1.4.3.1.3                                                1.4.3.1.3.1
                                                                                                     1.4.3.1.3
                  Generic: Sensor                                                                              Generic: Sensor
                  Analog output                       Generic: Sensor             Generic: Sensor
                                                      WARN - Loop should be       Choose analog output         Fld dev output is
                   1 AO1          13.467                                                                       fixed at 4.000 mA
                   2 AO Alrm typ                      removed from                level
                   3 Loop test                        automatic control             1 4 mA
                   4 D/A trim                                                       2 20 mA
                   5 Scaled D/A trim                                                3 Other
                  HELP SAVE HOME                                                    4 End
                                                                    ABORT OK                   ABORTENTER                      ABORT OK


                                                         } Menu windows are displayed but not
                                                           supported by the sensor.
                                                           Saving of the adjustments carried out
                                                           here, is hence not possible.


                                                                               1.4.3.2.3
                                                         Generic: Sensor
                                                         Burst mode                         Off               Sensor signals measured values only upon
                                                         Off                                On                request
                                                          Off                               Not used          Sensor signals measured values unsolicited
                                                          On                                None
                                                          Not Used                          Unknown            Choice is not supported
                                                          None                              Special
                                                                       ESC      ENTER
                                                                                                         Burst mode should be off
                                            1.4.3.2
                     Generic: Sensor                                            1.4.3.2.4
                     HART output                         Generic: Sensor
                      1 Poll addr                        Burst option
                      2 Num req preams                   *********
                      3 Burst mode                         PV
                      4 Burst option                       % range/current                      Choice is not supported
                                                           Process vars/crnt
                     HELP SAVE      HOME
                                                         HELP    ESC ENTER
                               Note:
                               After adjustment of a parameter push ”ENTER“ and then ”SEND“.
22574-EN-020809




                               Confirm the message to switch over the meas. circuit to manual operation
                               with ”OK“.
                               Confirm the message to change over to automatic operation also with ”OK“.
                               Only then the adjustment is written in the sensor and is effective.

                  Capacitive electrodes EK 4 … 20 mA - Compact                                                                                   35
                                                                                      Diagnosis


5 Diagnosis
5.1 Simulation

To simulate a certain filling level, you can call
up the function “Simulation” in the oscillator, in
the adjustment program VVO or in the HART®
handheld.
You hereby simulate a certain current. Re-
member that connected instruments, such as
e.g. a PLC, react according to their settings
and that alarms may be triggered or system
functions activated.


5.2 Maintenance

The instrument is maintenance-free.


5.3 Repair

Repair work requires opening the instrument
to correct defects. For safety and warranty
reasons, all internal work on the instruments,
apart from that involved in normal installation
and connection, must be carried out only by
qualified VEGA personnel.

In case of a defect, please return the affected
instrument with a short description of the error
to our repair department.

Faults are short-term malfunctions of the in-
strument which are caused by wrong adjust-
ment or defects in the sensor or the
connection cables.

Faults, their possible causes and their rectifi-
cation are explained under “5.4 Fault rectifica-
tion“.
                                                                                                    22574-EN-020809




36                                                   Capacitive electrodes EK 4 … 20 mA - Compact
                  Diagnosis


                  5.4 Fault rectification

                  Fault                    Rectifying measure
                  Current value            Check the sensor inputs for the following causes of faults:
                  ≥ 22 mA                  - short-circuit on the input
                                           - sensor not connected correctly
                                           - sensor cable interrupted
                                           - supply voltage too low or too high

                                           Measure the current on the connection cable to the sensor.

                                           Under normal conditions, the terminal voltage of the sensor is at least
                                           12 V.

                                                            4 … 20 mA    12 20 V
                                                                        12 …… 36 mA

                                                              mA           V

                                                                                        28
                                                                                             +   +
                                                    +                                   30
                                                                                             –   –
                                                    –                                   32



                                           Sensor
                                                                                      e.g. VEGATOR



                                                        In Ex systems, make sure that the Ex protection is not influ-
                                                        enced by the measuring instruments.

                                           Current value > 22 mA
                                           - Check all connections and the connection cable to the sensor.
                                           - Loosen the two small screws with a Phillips screwdriver and remove
                                             the oscillator from the plug connection.
                                           - Measure the current.
                                             •     If the current value remains > 22 mA, then the oscillator is
                                                   defective. Exchange the oscillator.
                                             •     If the current value is < 22 mA, the the electrode is defective.
                                                   Return the electrode for repair.
22574-EN-020809




                  Capacitive electrodes EK 4 … 20 mA - Compact                                                          37
                                                                                        Diagnosis


Fault               Rectifying measure
Sensor defective,   Test the internal connections:
Measurement does    • Loosen the 4 screws of the housing cover with a Phillips screw-
react to level         driver and remove the housing cover.
changes             • Loosen the two small screws with a Phillips screwdriver and pull the
                       oscillator out of the housing.
                    • Measure with an ohmmeter (range MOhm) the resistance values
                       between the following contacts:




                                     Screen
                                                       6
                                                             CM

                                               4             1M




                    CM - Capacitor




                    Contact 4 and middle pin (1)
                    The resistance must be 1 MOhm.
                    If the resistance is less, it indicates moisture in the housing or a defect in
                    the electrode insulation. A possible reason could be a non-insulated
                    electrode used in a conductive (moist) medium.
                    If the resistance is higher or if the connection is interrupted, the reason is
                    usually a bonding failure in the adapter plate or a defective resistor due
                    to strong electrostatic discharge.
                    In both cases, return the electrode to VEGA for repair.
                                                                                                      22574-EN-020809




38                                                     Capacitive electrodes EK 4 … 20 mA - Compact
                  Diagnosis



                                           Contact 4 and vessel
                                           The connection between contact 4 and the metal vessel (not instrument
                                           hexagon or electrode flange) should be as good as possible. Measure
                                           with an ohmmeter (range very low) the resistance value between contact
                                           4 and the vessel.
                                           • Short-circuit (0 … 3 Ohm), optimum connection
                                           • Resistance > 3 Ohm
                                             - corrosion on the mounting thread or flange
                                             - possibly the mounting thread was covered with Teflon tape or a
                                             similar material
                                           Check the connection to the vessel. If there is no connection, you can
                                           connect a cable from the external grounding terminal to the vessel. Make
                                           sure that coated flanges are always connected via the grounding termi-
                                           nal to the vessel.


                                           Contact 4 and 6
                                           Values > 3 Ohm indicate a defect.

                                           If you cannot find a failure in the electrode, then replace the oscillator with
                                           a similar type (if available) or send the electrode for repair to VEGA.
                                           After replacement of the electronics, a fresh adjustment must be carried
                                           out. See 4 Setup


                  VVO                      Invalid measured value
                  error message            The current measured value is outside the valid measuring range.
                  Invalid measured         Causes can be e.g. considerable changes of the DK value or incorrect
                  value                    settings.
                                           Change the current measuring conditions.


                  VVO                      Instrument error
                  error message            An error in the sensor was found.
                  Instrument error
                                           Possible causes are:
                                           - supply voltage not within tolerance
                                           - defective oscillator
                                           - damage to the electrode or to the insulation
                                           - electrode short-circuited against vessel wall

                                           • Separate the sensor from power supply and then reconnect (cold
                                             start).
                                           • If the error message does not extinguish, check the sensor cable and
                                             the power supply.
                                           • If the error message does not extinguish, check the sensor for visible
                                             damage.
                                             If you cannot find any faults, please call our service department.
22574-EN-020809




                  Capacitive electrodes EK 4 … 20 mA - Compact                                                          39
VEGA Grieshaber KG
Am Hohenstein 113
77761 Schiltach
Germany
Phone    (07836) 50-0
Fax      (07836) 50-201
E-Mail   info@de.vega.com
www.vega.com




                   ISO 9001




            All statements relating to scope of delivery, application, practical use
            and operating conditions of the sensors and processing systems
            correspond to the latest information at the time of printing.

                              Technical data subject to alterations

                                                                                 2.22 574-EN-020809

								
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