LCN/Climate: How to deal with temperature offsets

Configuration
1

Hello,

I am in the process to describe my LCN system within the newly established HA environment. The underfloor heating in my house is controlled by LCN-TS, which are installed in the wall in every room together with the modules. Due to the module waste heat, the TS measure a slightly higher temperature than the actual room temperature.

The offset is quite stable for each module (between +0.6 and 1.5 °C).I can correct a displayed temperature by defining a template for each individual sensor so that a dashboard will show the right number. Within LCN I can deal with this offset by increasing the programmed climate regulator value by an additional fixed offset. However, HA’s horseshoe control is then displaying the adjusted regulator value. For example, I want to have a temp of 21.0 °C in the room, in LCN-PRO I define 21.0 and then shift the setpoint by an additional +0.6 °C. Unfortunately for displaying purposes, HA’s horseshoe control now pulls the adjusted setpoint and displays 21.6 °C as desired temperature instead of the real 21.0 °C:
Temp

Is there any way to build around this and have the control display adjusted values? One possibility seems to use the Generic Thermostat for each module, but I can’t select any LCN temerpature sensor there.

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Hi @Sourcer63 ,
the LCN-ish way of handling temperature offset corrections would be to define a new module variable filled by a formula which calculates the correct actual value from the sensor (LCN-TS) variable minus the offset.

The calculated variable is then used for the actual regulator value (programmed with LCN-Pro).

In HomeAssistant you also need to use this calculated variable as the source for the actual value for the climate entity.

No need to shift any setpoints.
Wouldn’t that solve your problem?

Andre

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I had thought about this before, obviously not enough. :slight_smile: Thanks for retriggering my thought process - it works! :+1: :partying_face:

The situation here is that I have 9 TS, of which 8 are connected to old modules (Series 0D) that only have TVar, R1Var and R2Var. The trick is to store the LCN offset manually into TVar and use the second climate control to subtract it from R1Var which contains the TS reading:

TVar = 1006 (0.6 °C)
R1Var is the “wrong” temp reading
R2Var = R1Var - TVar to be used for the climate control
The Tvar offset is set in the module’s power failure properties by “adding” it both for short and long failures.

Regler