Document Sample
Glossary Powered By Docstoc
LAP                                                                                     LSOH
Link Access Protocol.                                                                   Low smoke and halogen-free (LS = low smoke)
                                                                                        (OH = zero halogen)
Light Amplification by Stimulated Emission of Radiation: Amplifier for                    LWL
electromagnetic waves in the visible light spectrum.                                    Fibre optics

Latency                                                                                 MAC
Delay time.                                                                             Medium Access Control

Latency time                                                                            Machine
Period of time needed by a device to react to an input event at the output              According to the Machines Directive, a machine means a totality of parts, at
or also the time which, e.g. a data packet needs to traverse a network from             least one of which is moveable, connected with each other. As well as the
sender to recipient or how long it remains in a network device before it is             mechanical components, operating, control and energy components also
forwarded.                                                                              belong to the machine.

Launch angle                                                                            MAN
Angle between the propagation direction of the light occurring and the                  Metropolitan Area Network (large area network, e.g. connection of several
optical axis of a fibre optic cable. In order for the light occurring to be              LANs within a city).
couples, this angle must be between zero and a maximum value which
depends on the location on the front surface of the thread or on its local              MAN
refraction difference as compared with the switching.                                   Metropolitan Area Network. For connecting different LANs within a city.

Lay-length                                                                              MAP
The axial length along the centre axis of a cable according to which a                  Manufacturing Automation Protocol - data transfer protocol for automated
stranding element is wrapped completely (360°) once around the axis.                    manufacturing.

LCIE                                                                                    Master
Laboratoire Central des Industries Electriques (France)                                 Central bus participant which regulates the bus access. All other participants
                                                                                        operate as slaves.
Light Emitting Diode                                                                    Master/Slave Concept
                                                                                        Master element determines, slave element follows the instructions
LID-System (Local Injection and Detection System)                                       of the master. For example, an automation device as master element grants
The LID system provides highly precise positioning of the fibres in the x/y              the access rights for the other components for the decentralised bus
and z directions. It consists of two bending couplers (sender and receiver).
The light is coupled into the fibres on the sending side. The transmitted
light power is measured at the receiving side. Criterion for the optimal
                                                                                        Motion Control
alignment of the fibres is the maximum of the light power transmitted
over the splice.
                                                                                        Medium Dependent Interface
Light speed
v0 2, 998 x 108 m/sec
Light waves
Electromagnetic waves in the optical frequencies range.
                                                                                        Meshed structure
The term “light” originally referred to the visible radiation with the
                                                                                        Every participant is connected with several others.
human eye with a wavelength between 400 and 800 nm. However, it
                                                                                        Several independent transmission paths can exist between two stations.
is also common to describe radiation in the adjacent spectral ranges
                                                                                        This redundancy can be used for assurance of the data transport if there is
(e.g. infrared) as light.                                                               an interruption of one transmission path.
Link                                                                                    MIB
Connection path between two nodes from and including the distribution                   Management Information Base. Contains the description of the connected
patch panel up to and including the work place connection socket.                       objects and functions in a network.
Link Aggregation                                                                        Microbending
Combination of several ports (max, 4) into one virtual port. Parallel                   Bending of a fibre which produces light losses and thus attenuation
connection transfer with redundancy if a port fails. Standard IEEE 802.3.               increases.
Commonly called “Trunking”.
LON                                                                                     Process of porting data or software to a different technical platform
Local Operating Network: open bus system which makes possible the
interaction of components from different manufacturers.                                 MII
Loss (attenuation) e.g. of a transfer line.                                             Media Independent Interface

Loop resistance                                                                         MIL
Ohmic complete resistance from transmit and return conductors (unit: W/km)              Military Specification (USA)

Low Voltage Directive                                                                   MLPPP
The aim of the directive is to ensure the safety of the consumers. It concerns all      Multi Link PPP. See also PPP.
electrical equipment for generating, transmitting, distributing, storing electrical
energy, e.g. generators, cables, switches, sockets and many others, for use with        MMI
a rated voltage between 50 and 1,000 Volts for alternating current and between          Man Machine Interface
75 and 1,500 Volts for direct current. Exceptions are regulated in Appendix II of
the Directive. Such equipment, according to the Directive, is only allowed to be        MMS
brought into circulation if it is manufactured according to the state of safety         Man Machine Interface (MMI)
technology specified in the European Union, it does not endanger people,
productive livestock and property during proper installation and maintenance            MODbus
and during proper use, it has been subjected to a conformity assessment                 Master / Slave network which makes it possible, for example, for a master
procedure by the manufacturer, there is a corresponding declaration of                  computer to communicate with one or several PLCs or Remote I/Os, to
conformity and it is marked with the CE marking.                                        perform program processes, data transfers or other operations.