We have multiple Allen Bradley PLC's running a detention center. They were previously running on RSLogics and connected via OPC DA. We have a driver now connecting directly to the PLC and are experiencing timeouts and connection failures. The PLC's are running a version 4.x.x firmware and are from about 2008. Running a diagnostic we receive no major or minor errors. But looking deeper into the webpage, we see thousands of CRC errors. On some as many as 1000 per hour or more. The PLC has 1 core and we moved the time slice to 70 communication / 30 ladder from 20 communication / 80 ladder which seemed to help immensely.
My questions are:
1. Should we be concerned about these CRC errors and are they the root of our connection issues? If so, how do we resolve them?
2. Is it possible that RSLogics was keeping the connection solid and because we were connected to it, we did not see any connection issues and the errors were not passed through to us?
Any feedback on this situation would be very helpful.