Profibus adapter showing fault.

Hello everyone,

We have a AB 1756 L55m13 controller and profibus adapter sst-pfb-clx. The adapter is connected to six Vfds (all Siemenes midimaster and micro master). We had changed profibus cables and connectors.Ever since we changed one of the VFd is blinking green and the profibus adapter has red light on sys led. I checked the manual it says error in communicating with one of the slaves.The only way we can get this working is powering down all vfd and plc and powering up again. Some times it runs for 2 days without any problems but again the problem shows up. What could be the problem. Please help

The shield is very important with Profibus and will cause errors that needs re-boot. Are these home made cables? Is the terminating switch in the proper position.

Have you had a look at System Diagnostics in Chapter 6 of the User Reference Guide? Look in the Status Data, and see if you can find an Error Code. This will narrow it down for you.

Stu.....

Terminating switches are in proper positions. Didnt go online yet. Btw can please elaborate about shielding. The thing is that runs for 2 3 days without any hitch then all of sudden it shows fault.

You may have to connect the shield to either one of the ends or both. I think it's a trial and error thing.

If you didn't use a shielded cable that could be a problem.

Profibus installation guide

http://www.profibus.com/fileadmin/media/wbt/WBT_Assembly_V10_Dec06/en/Seiten/index.html

I have experienced similar - however my issue was fixed using a newer GSD file.