Dean Novak

There were a few on the network port until we changed the time slice.  Now the remaining are on the backplane.  

This is a detention center and we are controlling the PLC from our application with an HMI operator interface.  Periodic task??  Are you referring to running the ladder once every 200MS instead of it spinning every 15MS?  Our application does not control that but I am sure we could set up the PLC to perform that way.   Thanks, let me look into that.  Any other advice?  Are these CRC  (FDS) errors concerning?  Our subcontractor seem to feel they are normal and fine.  I'm not convinced.  Previously we were connected via OPC DA.  RS Logics was in between and we did not see these issues, even though they existed.  I believe it handled these minor time outs and reconnects.  

Realizing this is only a 1 core device. We changed the time slice from 20% communications  / 80% ladder to 70% Communications / 30% Ladder.  That seemed to stabilize the communications considerably.  The models are 1756 L61, 1756 L63 and 1756 L71.  The errors are FDS errors.  Hundreds of thousands of them. We still are seeing intermitted timeouts and disconnections occasionally.  

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.