I contribution always at peak, no reaction to Ki setting

[denkmalnach]

Hi there,

I just stumpled over a problem with my first PID setup. I activated the diagnostic sensors, to see the contribution of the different parts.

What ever I choose for Ki the I contribution is always 3,0 when there is any error. Even with Ki=0 this behavior is not changing, which should deactivate the I contribution, as far as I understand the PID process.

I got a setup with a temperature sensor in a water boiler, that is heated by 3 x 3 kW electric heater.
I set up the output min / max to 0 / 3, and use an automation to turn the heaters on and off, according to the output.

greetings
Christian

[bvweerd]

Hi,

Please start with windup protection off, and very small values for k,i,d as a test.

Note that if your error is bigger than the boundaries you gave, it's not going anywhere.

Please upload your diagnostics info if we need to dig deeper.

[denkmalnach]

thx for the hint, i figured it out. the windup protection off was the right clue, so i could see the I contribution reacting better. I also had to increase my sample time, since the process is really slow.
seems like the option 'windup protection' clips off the I contribution to output max, but internally it can rise much higher, is this so?
Is there a easy way to restart the controller, so it can start with the desired start mode (for instance Zero Start)? I must confess, that I restarted the hole home assistant to achive this.

[bvweerd]

thx for the hint, i figured it out. the windup protection off was the right clue, so i could see the I contribution reacting better. I also had to increase my sample time, since the process is really slow.

Great!

seems like the option 'windup protection' clips off the I contribution to output max, but internally it can rise much higher, is this so?

No — in the simple-pid library, the windup protection (via output_limits) does not just clip the final output while letting the internal I-term keep rising.

Instead, when output_limits are set, both the output and the integral term are clamped within those limits. That means the integrator cannot continue to accumulate beyond the defined range — it’s actively constrained to prevent windup.

More info here: https://simple-pid.readthedocs.io/en/latest/user_guide.html#user-guide

Is there a easy way to restart the controller, so it can start with the desired start mode (for instance Zero Start)? I must confess, that I restarted the hole home assistant to achive this.

Yes, set auto-mode to off and on again.