Can't get my PID loop to auto tune

[siavash]

Hey guys,
So I've been struggling with this issue for a while now and I thought maybe someone has more experience here that can help out. We've been trying to implement a PID control loop on Do-More BRX PLCs but we haven't been able to get the auto tune feature to work. We have tried two PID loops, a heating loop and a pressure control loop. In both cases, auto tune runs as expected by the final values for gain, reset and rate are always the values we started with, but there are no auto tune errors, and according to the ladder logic the tuning process is running without any issues. Is there something I'm missing here?
All suggestions are much appreciated.

[franji1]

You mentioned that the "tuning process is still running" - that's not good.  It's still stepping through the process.

Do you get the dialog that tells you Auto Tune completed and whether you want to return control of the PID mode to Ladder Logic or continue to manually override the mode (AutoTune procedure overrides the loop mode).

Are you doing Open Loop or Closed Loop Auto Tune?

[siavash]

You mentioned that the "tuning process is still running" - that's not good.  It's still stepping through the process.

Do you get the dialog that tells you Auto Tune completed and whether you want to return control of the PID mode to Ladder Logic or continue to manually override the mode (AutoTune procedure overrides the loop mode).

Are you doing Open Loop or Closed Loop Auto Tune?

Thanks for the reply.
I should have been more clear, by tuning process is running with no problem what I meant was that all the relevant bits show that the auto tune process is completed without any issues (.AutoTuning to ON and then OFF, .AutoTuneComp to ON, and .AutoTuningErr to OFF). I do get the dialog that tells me that auto tune completed, but the values shown as the tuned parameters are the same ones I had set manually. I'm running closed loop on PI mode.

[franji1]

The only thing I can think of is you have  PIDINIT instruction or some logic or HMI overwriting the values? ? ?

[siavash]

You were right. There was some ladder logic that was overwriting the PID parameters before they could be identified. Thanks for the advice.