Siemens SIMATIC NET PROFIBUS manual Checking the Optical Signal Quality with Profibus OLM

Testing PROFIBUS

A.2.4 Checking the Optical Signal Quality with PROFIBUS OLM V3

The receive level of the two optical channels can be detected using a normal commercially available voltmeter attached to measurement sockets on the PROFIBUS OLM V3. The voltmeter can be inserted and removed during operation using 2 mm laboratory test plugs (see Figure A-6).

Figure A-6 Testing the Signal Quality on an OLM V3 with a Voltmeter

This allows the following:

SThe incoming optical power can be documented, for example for later measurements (aging, damage)

SA good/bad check can be made (limit value).

The correlation between the measured output voltage and the signal quality is in the form of a curve (see Figure A-7).

A-12	PROFIBUS Networks SIMATIC NET
	6GK1970-5CA20-0AA1 Release 2 05/2000