Viessmann thermometer

[eulaersi]

I've a Viessmann Vitodens 200 that is controlled through a Viessmann outside thermometer.

Can I use this signal from the thermometer and connect it to an analog input without disturbing the heat control? If so, I don't have to buy a second temperature sensor, and I would be able to use it for other purposes.

Best regards

Ivan

[mhanft]

If you use "Vitocom 200" as EIB interface, you don't need an analog input - the outside thermometer sends its value directly onto the bus.

I think the price difference between the Vitocom and an analog input is not too big.

Matthias

[Kaucher]

Hi Ivan,

It definitly doesn't work, to connect the outside-sensor to a second analogue input!

The Sensor is a PT500 thermo-resistor. The VITODENS sends a current through it, to mesure the resistance and calculate the according temperature.
If you connect a second PT500-compatible analogue input, this input will also send a measurement-current.

Both will disturbe each other and it won't work!

Even if it would work, the VIESSMANN 'PT500' is different from a standard 'PT500' according to DIN.

It has a different characteristic curve, so you'd have to re-calculate the temperature values to the Viessmann curve.

Best regards

Jörg