Why is my PID not turning off the selected output

Hello all,

I have a question about my PID configuration. I am setting up a new Mycodo setup for my koji fermentation chamber. I already have a older version of Mycodo running for my curing chamber.

Unfortunately, I am having issues with my PID setup. I am trying to raise the temperature to 30 degrees celcius. If the current temperature is below 30 degrees celcius, the output is turned on. But if the temperature is above 31.5 degrees (setpoint + band), it is not disabling the output. Do you guys have some advice what I could try. I am running mycodo 8.15.9. On my older system I am using 8.13.2. Is there a difference between these two systems?

Thank you in advance.


There are so many things that can cause this, without knowing your configuration, it’s impossible to provide any feedback. It likely comes down to user error with a misconfigured PID controller. Looking at your immense P value, there is something not configured correctly with your controller. This is why it it generally advised to not use a PID controller for regulation if you’re not familiar with the theory and tuning process. PID controllers are an advanced control system component and you can’t expect a PID controller to operate properly if it’s not properly tuned.

Hi KyleGabriel

Thank you for your response.
I have an idea how PID controllers work. But somehow I am confused why my relay is not disabled when the output is negative. When I use ‘both’ directions, I thought that a positive number would trigger the ‘raising’ and a negative would trigger a lowering. The huge P value is my setup to test this assumption.
But I will tune down the parameters to callibrate the 3 values.
Thanks again!

Again, without providing your configuration, nothing can really be done to help.