We experienced the exact same thing on CP60's that had both FBM200s and FBM100s. We were receiving constant PIO Bus faillure notices. Foxboro has a customer advisory or helpful hint that solved our problem, it talks about ground problems on the fieldbus for CP60's. This document was close to 40 pages long. I do not know the reference number but your Foxboro field service man should be able to assist you. We had our Foxboro representative down to fix the problem, but we were in an outage at the time. Since the grounding corrections have been made, we have not seen the problem recur. You would have to talk to Foxboro to see if the corrections could be made while running the unit. _______________________________________________________________________ This mailing list is neither sponsored nor endorsed by Invensys Process Systems (formerly The Foxboro Company). Use the info you obtain here at your own risks. Read http://www.thecassandraproject.org/disclaimer.html foxboro mailing list: //www.freelists.org/list/foxboro to subscribe: mailto:foxboro-request@xxxxxxxxxxxxx?subject=join to unsubscribe: mailto:foxboro-request@xxxxxxxxxxxxx?subject=leave