Simens Profibus Problem 6ES7151-1AA05-0AB0

Hi, we have been having a problem with a profibus station on a machine with adapter number 6ES7151-1AA05-0AB0. Most times the machine would start and work well however the red SF led would flash on briefly and then go off (very random, no sequence). Sometimes when the machine is turned on the SF led would be Stead On and the BF light flashing. We have tried changing the profibus cable, connector and interface module but the problem is always the same. Note too that there are other modules in this network both before and after that are working without error.

The fault buffer shows the 12th module is faulting intermittently. The base for this module was changed but not the module itself (awaiting replacement) and the problem still exist.

Has anyone experienced a problem similar to this or can offer some options as to what else could be the problem?

Hi!

Try searching the forum with 'profibus grounding'. You'll get lots of hits, this one among others:

http://www.plctalk.net/qanda/showthread.php?t=75048&highlight=profibus+grounding

Kalle

Thanks KalleOlsen

I am looking into this at the moment, in your experience can these grounding problems create problems that affect only one node in a cabinet and other nodes right next to it have no problems?

Check grounding
If frequency inverters - Check installation and EMC precautions

Check List During Commissioning of a Profibus Network
•Profibus wire polarity (A=green, B=red) should be correct.
•Ensure maximum 32 devices or less per segment.
•Only two terminating resistors inserted
•Guaranteed power supply for terminating resistors (even in case of emergency stop)?
•Avoid branch lines.
•Use only Profibus cable and connectors
•Cable trays grounded
•Multiple Profibus cables laid inside the same metal conduit gives good behavior when EMC is involved.
•Shielding is applied to the PROFIBUS stations, and connected to ground?
•Adequate baud rate is set with respect to cable length.
•Ensure that the address of each node is defined correctly.
•In case of higher transmission speed, the minimum distance between two devices shall be at least one meter.
•One slave device can’t have two masters.

Kabir said:

Thanks KalleOlsen

I am looking into this at the moment, in your experience can these grounding problems create problems that affect only one node in a cabinet and other nodes right next to it have no problems?

Click to expand...

Yes. I can guess, but you can measure

Kalle