Help With Problems During Operation - Siemens SIMATIC NET PG PROFIBUS Operating Instructions Manual

Help with problems during operation

6.1 Help with problems during operation
LED display
L+ 24 V LED not lit
L+ 24 V LED flashes
CH1 LED not lit
CH1 LED lit
PROFIBUS nodes are, however, signaling problems on the
bus
CH2, CH3 LED not lit
CH2, CH3 LED lit
PROFIBUS nodes are, however, signaling problems on the
bus
If no LED indicates an error and you are still experiencing problems in communication (for
example an acknowledgement is not received, unexpected frames), you should check the
monitoring times set on the PROFIBUS nodes (for example the slot time). You will find
details in the description of your PROFIBUS end devices and your configuration software.
PROFIBUS Optical Bus Terminal (OBT)
Operating Instructions, 04/2016, C79000-G8976-C122-07
Possible cause of problems
Power supply failed
•
OBT defective
•
The transmission speed could not be set
•
One or more wires of the RS-485 bus cable is interrupt-
•
ed
Wires A and B of the RS-485 bus cable had been
•
swapped over
Connected PROFIBUS node is defective or is not trans-
•
mitting
PROFIBUS node or RS-485 segment is not connected
•
or connected or PROFIBUS node is not turned on
Wires A and B of the RS-485 bus cable had been
•
swapped over
Short circuit on the RS-485 bus cable
•
Interruption of one of the two wires of the RS-485 bus
•
cable and A or B connected to wrong terminal
Missing or incorrect termination
•
Send and receive FO cable connected to wrong socket
•
Interruption of the receive FO cable to the partner mod-
•
ule
No partner module connected or connected partner
•
module is not turned on
Connected partner module is defective (not transmitting)
•
FO cable connector is loose (bad contact)
•
FO cable link to the neighboring module is too long
•
Interruption of the receive FO cable with extraneous light
•
entering
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