Hello,

I have a error in red profibus, When the machine is running, the profibus mark an error and stop the machine. The error is different every time. Profibus 3 error, Profibus 4 error and etc.. How I see the problem?

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Split from Detect an Profibus error without Profibus Analyzer.

Hello Rulmon;

What PLC are you using, and what programming software (and version are you using?

Is there an OB86 (diagnostic OB for Rack Failure) in the PLC program? If OB86 is loaded in the program and a Profibus error comes up, the PLC will not go to STOP (unless other diagnostic oBs are requested, see the messages in the diagnostic buffer of the CPU).

But you will still have errors (they will be logged in the diagnostic buffer) and they miust be corrected for the PLC to run smoothly.

So: start by checking the diagnostic buffer to see what messages come up, and to see if diagnostic OBs are missing or requested; simply create them in the blocks folder, without a line of programming (for now) and download them to the CPU.

Next, check the Profibus cables and connectors, it  will happen over time that the cable connections will become loose in the connectors (vibrating machines are more subject to this); and specially check the termination resistors at each end of the bus (on the first and last physical nodes of the network): they must be ON at each end stations, but OFF on all other nodes. 

Tell us if this helps,and save the buffer messages to post a copy here if you need help understanding them.

If you are willing to spend a bit of time with documentation, I suggest you go to the download page of Profibus.com and open the Installation Guide section, where you can find a Profibus installation guide, and a Profibus Interconnection guide that should guide you in your troubleshooting.

http://www.profibus.com/download/

Hope this helps,

Daniel Chartier