error 41555

tomus50

i am wondering if anyone else has experienced the same problem.
IRC5 / 6600 stacking robot connected to a Siemens plc via profibus.
equipment  is approx. 7 years old and the error has only recently developed.
periodically getting this error, 41555 : no contact with unit Pbus.
 i have replaced the devicenet pci and the dsqc 352a.
not sure where to look from here.
any suggestions?

thanks

graemepaulin

Has there been any electrical equipment added or replaced that could be causing interference/noise on the communication cable?

Shielding and wiring connections at all points in the communications circuit still have good connections.

tomus50

nothing has been changed. we have a Softing profibus tester and everything seems normal.

actually better than some of the other systems we have.