PIDE output changing to 100% intermittently

we have PIDE configured in L71 Control Logix controller, at times its observed that PIDE output changes to 100% without any change in PV or SP. we two control valves PCV-1 & PCV-2 with individual PIDE with common PV both controller output changes to 100% on its own without any change in PV or SP
Can somebody help me to resolve this issue - Thank you

We would need more information.

• How do you detect that the CV output is going to 100%?
  • How long (or for how many PLC scans) does it stay at 100%?
  • Could you make a trend, of CV, PV, SP, and perhaps some PIDE-internal values, that is triggered by the jump in CV, and includes a few dozen scans before, and samples at every scan?
• How do you know that PV and SP are not changing?
  • What is the sampling time that you are using e.g. are you watching the values in Studio 5000?
• Can you post all of the configuration and tuning parameters for the PIDE instructions?
• Can you describe the process e.g. what the PV is (flow, temperature, pressure, etc.) and how fast it moves, where the SP comes from, where the CV goes, what the valves driven by the CV control, how fast the valves can move, etc.?
• Can you post your code and project, ideally as a PDF?

Thank you very much indeed sir, I suspect the SP value is changing to zero. This SP value is written from Honeywell DCS to PLC via mod-bus gateways. i believe the communication is failing which is causing the SP value in PLC set to zero. we do not have HMI at PLC panel for historical trends and alarms. we historized the read write data to PLC in DCS with scan period of 5 seconds.

I would get all the info SP, PV and Output in a trend in Studio5000 and sit and watch it, that will reveal what is happening.

If you're getting a drop out momentarily, watching the screen wont necessarily pick it up.