Defining The Receiving Level Of The Optical Ports - Siemens SIMATIC 500 Series Description And Operating Instructions

4 Setting Up
L1+ / +24 VDC
F1
M /
F2
L2+ / +24 VDC*
Fig. 14: Signaling contact – pin assignment 5-pin terminal block

4.4.7 Defining the receiving level of the optical ports

Measuring sockets
Reference potential
Fig. 15: Location of the measuring sockets
26
PROFIBUS OLM
System
CH 1 CH 2 CH 3
CH 2
CH 3
Receive
Signal
Intensity
GND
Pin assignment, 5-pin terminal block:
terminals F1 and F2.
Always ensure that the pins are correctly assigned at
the 5-pin terminal block. Make sure that the connecting
leads of the signaling contacts are adequately insula-
ted, particularly if you are working with voltages greater
than 32 V. Incorrect assignment can lead to destruction
of the module.
The receiving level of the two optical Ports CH2 and CH 3
can be measured using a conventional voltmeter con-
nected to the measuring sockets. The voltmeter can be
connected and disconnected while the module is in
operation without any interference using 2 mm laboratory
test plugs.
The OLM is protected against short circuits at the measu-
ring sockets, although data transmission may be briefly
disrupted*.
With this
– the incoming optical performance can be documented,
e.g. for later measurements (ageing, damage)
– a good/poor check can be carried out (limit value).
Further information can be found in Appendix 8.8
"Measuring sockets" p.38.
* Only an ungrounded, high-resistance voltmeter may be
used to take measurements.
The reference potential socket may not be connected to
the OLM housing.
4.4 Installation
Version 2.1 10/01