Siemens SIMATIC NET PROFIBUS Defining the receiving level of the optical ports, Measuring sockets

4 Setting Up 4.4 Installation

L1+ / +24 V

F1

M /

F2

L2+ / +24 V*

Fig. 12: Signaling contact – pin assignment 5-pin terminal block

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.

4.4.6 Defining the receiving level of the optical ports

		PROFIBUS OLM
	System
			CH 1 CH 2 CH 3
Measuring sockets		CH 2
		CH 3
		Receive
		Signal
		Intensity

Reference potential GND

Fig. 13: Location of the measuring sockets

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 8.4 ”Measuring sockets“ p.35.

*Only an ungrounded, high-resistance voltmeter may be used to take measurements.

The reference potential socket may not be connected to the OLM housing.

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