Troubleshooting/Faqs - Siemens SIMATIC NET Operating Instructions Manual

Troubleshooting/FAQs

This section will help you to localize the problem after an error is signaled (LED or signaling
contact). Refer to the description of the LED displays in section "LED display (Page 13)".
Error display of the System LED
See description of the LED displays in the section "LED display (Page 13)".
Error display of the "CH1"/"CH0" LEDs
Check whether
● the DIL switch S0 (CH1) or S8 (CH0) is in position 1 when the OLM is in the electrical star
segment of a star topology, see section "Star topology (Page 57)"
● the problem remains after removing the RS-485 connector.
Still there: Device defective
Gone: The error is in the RS-485 bus segment.
Check
– all RS-485 connectors as described in section "Electrical RS-485 bus cables
– the setup and the shielding of the RS-485 bus segment
– the RS-485 bus segment using the PROFIBUS bus monitor
– the configuration of all bus nodes
Does not apply if the monomaster of a PROFIBUS network is connected to the RS-485 bus
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segment to be tested. In this case, replace the suspect OLM with another OLM from the
network and then carry out the test mentioned above.
If the error moves with the OLM, the device is defective. Replace the OLM.
If the problem does not move with the OLM, the disturbance originates in the RS-485 bus
segment. Take measures as described above.
Optical link module
Operating Instructions, 01/2020, C79000-G8976-C270-06
(Page 44)"
Replace the OLM.
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