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Using the PC830 with a Trilogy Linear Motor with Encoder Based Commutation for
firmware version 1.80+

Last Update: 9/26/00 by John Bundschuh

The PC830 drive can commute a motor using either an incremental encoder, a hall/encoder
(comcoder), or a resolver for feedback. However, a few preliminary steps are required to be
taken when wiring up an incremental encoder for primary feedback.

Wiring up the PC830 Drive to a linear motor:

Wiring up the Motor Feedback: Connection J3-1,6,8,9,10,11,12,13,14,15
Short pins J3-1 and J3-6 to “fool” the resolver excitation signal being sent from the drive into
thinking that a resolver has been connected. Next, connect the PTC and PTC return (motor
thermostat) signals from the motor to J3-8 and J3-9 respectively. See appendix – section 1 for
wiring setup for Trilogy linear motors to the PC830.

The encoder feedback is wired into J3-14 (A), J3-15 (A/), J3-12 (B), J3-13 (B/), and J3-11 ( I/O
RTN). An external power supply is need for the LEM. The LEM needs 5 vdc @ 700 mA. The
PC830 can provide only 5 vdc @ 200 mA. It is recommended to add two 150-1/4 watt
resistors to sharpen the encoder pulse train input edges…short one resistor between A and A/ and
the other between B and B/.


Wiring up the Motor Power:           Connection TB1-10,11,12,13
Wire the motor power phase leads to the drive (see appendix – section 1 for wiring setup for
Trilogy linear motors to the PC830).


1.   Click on the Create New Configuration button.
2.   Select an R88H motor (this is merely for initial testing purposes).
3.   Select the appropriate drive model.
4.   Select Mode of operation:

    Position Mode – Predefined Moves
    Position Mode – Step & Direction
    Position Mode – Electronic Gearing
    Velocity Mode – Analog Command
    Velocity Mode – Serial Command
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    Torque Mode – Analog Command (Force Mode)
    etc

5.   Click Next.
6.   Digital I/O
    Input 1 -> Fault Reset (Hi)
    Input 2 -> Clockwise Inhibit (Hi)
    Input 3 -> CCW Inhibit (Hi)
    Input 4 -> Home Switch
    Output 1 -> Fault (Lo)

7.   Loop gains
    ARF0 =1500 Hz
    ARF1 = 1500 Hz
    Position Mode  Kvp = 0.3, Kvi = 5, Kpp = 15 & Kvff = 0
    Velocity mode  Kvp = 0.3, Kvi = 5, Kpp =0 & Kvff =0
    Torque mode    Kvp = 1, Kvi = 0, Kpp = 0 & Kvff = 0

8. Feedback
 Communtation source -> Comcoder (Hall/encoder)
                       If halls are not present, select -> Incremental encoder
                       Phasing gains; Kpenc, Kienc & Kdenc need to be set for phasing
9. Select Download to Drive and NVSAVE.
10. Click Finish and then select NO.
11. Ensure the hardware input is set for Disable!
12. Turn AC power OFF. Turn AC power ON.
13. Select Edit Drive Config Online and set the following parameters:
 CommEnbl = 0 (Disables “normal” commutation)
 CommScr = Comcoder (Hall/Encoder)
 Encin = 3048 linecount (5 um scale)
 EncMode = 0
 IlmtPlus = 22 % (Motor Icont/Drive Ipeak) *100 “percentage of the drives peak current in
                                                        Positive direction”
 IlmtMinus = 22% (Motor Icont/Drive Ipeak) *100
 Inp2Map = Clockwise Inhibit (Hi)
 Inp3Map = CCW Inhibit (Hi)
 Inp4Map = Home Switch (Hi)
 Kii = 50 Hz
 Kip = 25 volts/Amp
 Polecount = 2
 RemoteFB = 2

Click on ->NvSave

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11. With the motor disabled, select the variable EncPos from the Online Drive Config screen
    using 830Tools software and determine if it is polling the correct amount (e.g. Trilogy’s
    LM210-2 linear motor will poll 12192 encoder quadrature counts (encoder set for a 5 micron
    resolution) every 2.4 inches (this is the motor’s “electrical cycle”).
12. Select HallState. As the stage is moved positive, HallState will sequence
    (…6,4,5,1,3,2,6,4…)
13. Select Inp2, Move stage to positive limit. Inp2 =1 on limit and =0 off limit.
14. Select Inp3, Move stage to negative limit. Inp3 =1 on limit and =0 off limit.
15. Select Inp4, Move stage to home sensor. Inp4 =1 on sensor and =0 off sensor.
14. Enable the drive by asserting the hardware enable input.
15. If motor has an excessive ringing sound then consult section of this application note related
    to the calculation of Kip. Set this newly calculated Kip value in the Online Drive Config
    screen (NVSAVE this value as well).
16. Closed “Edit Drive Configuration Online”. Select “Upload Configuration from Drive”,
    >>Next, Save to File.


    How to check Motor wiring:
   Record the current value of ENCPOS.
   Next, set COMMOFF to 10 and record ENCPOS again.
   If the motor power wiring is correct, the motor should move in the direction that makes
    ENCPOS increase positively. If ENCPOS decreases, then the wiring is not consistent. Flip
    any two motor power leads and check that the motion is now consistent by repeating steps 11
    through 15 again.

    Calculating Encoder Line Count (EncIn)
    EncIn sets the line count expected by the PC830 for every motor electrical cycle. EncIn will
    determine the number of encoder lines per motor electrical cycle (see appendix – section 3).
    EncIn will be determined by the following relation:

                CountsPerElecCycle =                4 * EncIn / (PoleCount / 2)

    Since PoleCount is fixed at a value of “2” for ALL linear motors, this relation will simplify
    to:

                CountsPerElecCycle =                4 * EncIn

    CountsPerElectCycle is determined by the resolution of the encoder AND the motor’s spec
    for the electrical cycle. An example calculation follows for an LM210-2 Trilogy motor (5
    micron encoder resolution AND 2.4 inches per motor electrical cycle):

    CountsPerElecCycle = (1 encoder count/(5*10-6 m))*(1 m/1000 mm)*(25.4 mm/1 in)*(2.4 in/1 elec cycle)
                       = 12192 quad counts per electrical cycle

    EncIn       = CountsPerElecCycle / 4
                = 12192 quad counts per electrical cycle / 4
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                 = 3048 lines per electrical cycle




Parameter                           Value                              Comment
PoleCount                           2                                  Fixed constant for linear motors
Kip                                 See step 9                         Proportional gain for the current
                                                                       loop
Kvp                                 See step 10                        Proportional gain for the velocity
                                                                       loop
IlmtPlus                            See step 11                        Percentage of the drives peak
                                                                       current in clockwise direction
IlmtMinus                           See step 11                        Percentage of the drives peak
                                                                       current in counter-clockwise
                                                                       direction
EncInF0 (see appendix –             1600000 Hz                         Setup drive for maximum encoder
section 4)                                                             input frequency. See appendix –
                                                                       section 4.
EncMode                             0                                  Setup drive for a quadrature
                                                                       encoder
VelLmtHi                            21000 rpm                          Setup drive for maximum positive
                                                                       velocity
VelLmtLo                            -21000 rpm                         Setup drive for maximum
                                                                       negative velocity

      Calculating Kip
      Kip is the proportional gain for the current loop and it can be calculated based upon the motor
      line-line inductance (see motor spec) as per the following formula where the inductance is
      specified in Henries and NOT milliHenries (see appendix – section 2 for an example
      calculation):

                 Kip (V/A) = Ll-l * 2 *  * 1000

      Calculating Kvp
      The proportional loop gain for the velocity loop is Kvp and has an extensive calculation
      associated with it. The formula for Kvp is as follows (see appendix – section 2 for an example
      calculation):

         Kvp = 2 *  * BW * Mtotal * PoleSpacing / (0.867 * Kt)

         where   BW is the velocity loop bandwidth
                 Mtotal is the total mass of the load
                 PoleSpacing is the linear electrical cycle distance
                 Kt is the force constant of the motor




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   Calculating BW
   Bandwidth (BW) is a reflection of the system’s capable performance. Typically, bandwidth
   will range between 25 Hz and 200 Hz. Generally, a bandwidth of 50 to 75 Hz will be
   adequate for most systems. See appendix – section 2 for an example calculation.

   Calculating Mtotal
   The total load mass (Mtotal) is calculated based upon the motor plus the motor loads total
   weight as per the following relation (see appendix – section 2 for an example calculation):

               Mtotal [lbf/(in/sec2)] = Weight (lbf) / 386 in/s2

   Calculating PoleSpacing
   There is no calculation for this parameter. The motor manufacturers spec sheet should list
   the pole spacing for the linear motors. As an example, Trilogy specifies their linear motor
   pole spacing as 2.4 inches per electrical cycle for most of their motors.

   Calculating Kt
   The motor torque constant (Kt) is calculated from Ke (see motor data spec sheet) as per the
   following formula (see appendix – section 2 for an example calculation):

               Kt (lbf/A) = 8.85 * Ke (V/in/sec)

   Calculating IlmtPlus/IlmtMinus
   The drives peak current limits (IlmtPlus and IlmtMinus) are calculated based the motors rated
   current using the following relation:

       IlmtPlus = [constant * Imotor_rated (rms) / Idrive_peak (rms)] * 100%
       IlmtMinus = [constant * Imotor_rated (rms) / Idrive_peak (rms)] * 100%

   The constant term is multiple of the motor continuous rated current. Typically, motors will
   have a constant of 2 or 3 (meaning two or three times the continuous rated current of the
   motor). Consider the fact that the IlmtPlus/IlmtMinus values determine the peak output
   current from the PC830 drive, so the peak current may exceed the motor’s continuous rated
   current depending upon the value of IlmtPlus/IlmtMinus.


1. The motor should perform its encoder alignment check upon power up AND assertion of the
   hardware enable input. This alignment check will consist of a few diagnostic checks and
   some brief motor movement. The total encoder alignment check will last for approximately a
   few seconds after power up. Once the motor has been properly aligned, the drive/motor
   combination is ready to go.

   For additional information on incremental encoder alignment consult the online help of the
   PC830 software “Encoder Alignment Overview” or contact Pacific Scientific Applications
   Engineering for assistance.

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APPENDIX

Section 1
110, 210, & 310 WD2 All 410 & All WD3             PC830 Amplifier         Function
         Coils             Coils
      Red & Blue           Red                         TB1-11              Phase U
    Black & Brown         Orange                       TB1-12              Phase V
   Green & White          Brown                        TB1-13              Phase W
 Motor Cable Shield Motor Cable Shield                 TB1-10               GND
        Yellow             Grey                         J3-8                 PTC
       Orange              Violet                       J3-9               PTC Rtn

         LEM               PC830 Amplifier           Function
          J2-1              No Connection         LEM Power from external supply
          J2-2                   J3-11                  GND
          J2-3                   J3-14                    A
          J2-4                   J3-15                   A/
          J2-5                   J3-12                    B
          J2-6                   J3-13                   B/
         J2-23                    J3-1                 Hall A
         J2-24                    J3-2                 Hall B
         J2-25                    J3-3                 Hall C
          J2-9                   J2-32                 + Limit
         J2-10                   J2-33                 - Limit
         J2-11                   J2-34             Home switch
         J2-12                   J2-40              Limit Pull up
         J2-13                   J2-39              Digital Gnd
         J2-22                   J2-16                I/O Rtn
                            J2-16 – J2-39          Connect Gnd
                             J2-39 - J2-3          Connect Gnd
                              J3-1 – J3-6         Jumper resolver




Section 2
The following is an example controller setup for the calculation of the gains for a LM210-2 Trilogy linear motor
setup for position mode at a 75 Hz bandwidth using a 5 micron resolution encoder and a PC832. Use this example
as a reference for calculating the gain values for your particular linear motor as these values will depend upon the
linear motor being used – see motor specs).

    Example Controller Setup Values (based upon a LM210-2 Trilogy motor):

         Kip (V/A)         =        Ll-l * 2 *  * 1000
                           =        0.0048 H * 2 *  * 1000
                           =        30.16 V/A

         Kt (lbf/A)        =        8.85 * Ke (V/in/sec)
                           =        8.85 * 0.5 V/in/sec
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                           =         4.425 lbf/A

         Mtotal [lbf/(in/sec2)]      =        Weight (lbf) / 386 in/s2
                                     =        0.6 lbf / 386 in/sec2
                                     =        0.00155 lbf/in/sec2

         PoleSpacing       =         2.4 in/electrical cycle

         BW                =         75 Hz (desired bandwidth)

         Kvp (A/electrical cycles/sec)        =         2 *  * BW * Mtotal * PoleSpacing / (0.867 * Kt)
                  =         2 *  * 75 Hz * 0.00155 lbf/in/sec2 * 2.4 in/electrical cycle / (0.867 * 4.425 lbf/A)
                  =         0.457 A/electrical cycles/sec

         Kii (Hz)          =         50 Hz

         Kvi (Hz)          =         BW / 15
                           =         75 Hz / 15
                           =         5 Hz

         Kpp (Hz)          =         BW / 5
                           =         75 Hz / 5
                           =         15 Hz

         PoleCount         =         2

         IlmtPlus/IlmtMinus          =        [2 * Imotor_rated (rms) / Idrive_peak (rms)] * 100%
                                     =        [2 * 1.626 Arms / 5.3 Arms] * 100%
                                     =        61%

    CountsPerElecCycle = (1 encoder count/(5*10-6 m))*(1 m/1000 mm)*(25.4 mm/1 in)*(2.4 in/1 elec cycle)
                       = 12192 quad counts per electrical cycle

         EncIn             =         CountsPerElecCycle / 4
                           =         12192 quad counts per electrical cycle / 4
                           =         3048 lines per electrical cycle

Section 3
This application note refers to the term Encoder Resolution as the offset distance (phase difference) with respect to
channels A and B. As an example, if an encoder has a resolution of 5 microns and a linear motor were to have
moved 50 microns we would then expect 10 transitional pulses to have occurred.




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Section 4
The SC900 has a hardware quad count limitation (encoder frequency limitation). The limitation of the drive can be
extended by setting the EncInF0 filter to its maximum value of 1600000Hz. This will allow the drive to theoretically
achieve a maximum hardware quad count of 3,333,333 Hz under ideal conditions (ideal timing with exact 50% duty
cycle, perfect quadrature symmetry, etc.). A more realistic hardware quad count limitation would be somewhat less
than the EncInF0 value.




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