Delay with Closed Loop Pid Tuner

I need to tune the PID for a Geared DCX Maxon 32L Brushed DC motor for a peristaltic pump application with STM32 F413ZH controller

(I have already tuned it manually with gains from the Simuation model modified seems to running fine)

I need to control the flow rate of fluid being pumped basically RPM x Stroke so basically RPM control

RPM is derived from Encoder feedback decoded with theta delta divided by the time step kept using a dedicated timer

(If fixed model time step value used, based on model complexity delays introduced which mess with RPM calculation in Monitor and Tune)

However this dedicated timer seems to be causing errors with the Closed Loop PID auto tuner

And if I divide the theta delta with fixed time step, the delay introduced by tuner is too much (went from 40RPM to 1000RPM once tuner enabled)

Any solutions around this?

[Mathieu NOE]

hello

I just wonder if your problems are due to too fast sampling ... what is thetypical rpm range and what is the correspondig delta theta from the encoder ?

I would rather think that for such application a single pulse per shaft revolution would suffice (so delta theta is not a tiny fraction of 2 pi which relax the contsrain on the sampling rate and increases the rpm computation accuracy)