Sensor error with PT100 via Mosfet

[axiom]

Hello,
I'm trying to address my heating bed with dautherboards V1.2 on Duet2 Wifi.
The test with the supplied resistor works, about -3 degrees are displayed. If I then run the sensor via the mosfet (Wisamic 30 amps), the message Sensor hardware error appears. If I connect the sensor cables directly to the board, no sensor error is displayed.
What can be the reason for this, do I have to change something in the settings or do I have to connect it differently (drawing/plan)?

[dc42]

@axiom what do you mean by "If I then run the sensor via the mosfet" ?

[axiom]

@dc42 I have an 800x800mm heated bed. This is to be heated with 4 heating mats of 400 watts each. Therefore, I have 4 power supplies, each 1000 watts, which are to be controlled by mosfets. I have 2 PT100 daughterboards for the Duet2 Wifi. From dart the thermistors are supposed to go to the mosfet and then regulate them. Currently I have only put one heating bed into operation for testing.

[axiom]

@axiom Here some fotos to see the situation:

[axiom]

@axiom