Thanks for the advise.

This is a new installation. We checked the Profibus wiring, shielding/grounding and end termination- ->all seems OK. We also laid a temporary Profibus cable just laying on the floor suspecting that it was due to interference from power cables in the cable tray but when we switched ON, the IM151 of the first and 2nd station can no longer be accessed (BF flashing). When we interchanged the 1st and last, we now have the 1st and 2nd good and the problem is in the last station. I remember that during the initial start-up, it was the last station that was not accessed. We interchanged the 1st and last but the same. It was only when the DP constant bus cycle (32ms) and slave sychronization was activated that all were connected. However, while running, the intermittent problem from the 2nd station I described was coming. I suspect that the last station is already faulty --advise please.

I really do appreciate your technical support. best regards.....

The software you refer must be a good tool but unfortunately, I can not install it on my PC running on Windows Vista Business. I am a comissioning engineer and I am on site here in algeria.

Thanks for your support.

best regards,

Sly

I apologize for delay in informing you that we already solved the problem after we made isolation by running new cable from the PLC to each one of the ET200s IM151-1. Actually it was a bad wiring termination at the PLC side which we only noticed when we made a new termination for the isolation test. The green wire has damaged insulation and one strand of the shield happens to touch the open insulation. We never suspected it because it was inside the cabinet and was terminated by our panel contractor. We always make the checking only on the wiring done by the customer.

Anyway, thanks a lot for all your support and advise.

best regards,

Sly