Feature Request: Reverse mode (cooling logic)

[Yocee84]

Hi,

First of all, thank you for this great and clean PID controller integration – it's working perfectly in heating applications.

However, there’s a significant limitation when trying to use this integration for cooling scenarios, such as chilled ceiling panels or floor cooling systems.

Currently, the PID logic assumes heating behavior:

The lower the input sensor value compared to the setpoint, the higher the output.

In cooling applications, we typically want the opposite:

The higher the input value (e.g. supply water temperature) compared to the setpoint (e.g. dew point + 1 °C), the higher the output should be – to open the valve or activate cooling power.

Could you please add a reverse: true/false configuration option to the PID sensor?

reverse: false → classic heating PID logic (current behavior)

reverse: true → invert the output calculation, i.e. error = input - setpoint

This would allow users to seamlessly use this integration for both heating and cooling, without needing to:

swap the input and setpoint sensors (which makes the logic harder to follow), or

build inverse logic in Home Assistant automations (100 - PID_output)

Thank you again for your work, and we'd be happy to help test or review such an addition if needed!

[bvweerd]

The integration is based on the library simple-pid. The docs mention the use of negative numbers for reverse mode: https://simple-pid.readthedocs.io/en/latest/user_guide.html#reverse-mode.

Would that fit your needs? If so, I have to change the input values to allow negatives as well.

[Yocee84]

Thank you, that makes sense — using negative kp, ki, and kd values is a valid and flexible way to implement reverse-mode behavior for cooling systems. I fully agree that allowing negative values in the config would address the core need.

That said, I still think a simple reverse: true/false option could be helpful from a usability perspective — especially in setups where users want to dynamically switch between heating and cooling modes based on season or system state.

So while it's not strictly necessary, I believe a reverse flag would make the integration even more approachable for broader use cases — especially for less technical users.

[bvweerd]

I chose to implement it in line with the simple-pid library for now in v1.3.0. Thanks for contributing!