error 41555

Robot Controller
1

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

2

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.

3

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

actually better than some of the other systems we have.