Adding Nibe S-series (S1255-PC6) fails

[ArnoPW]

I'm trying to add my Nibe heatpump but validation fails with:
chargeStatus: read failed: modbus: exception '1' (illegal function), function '4'

I do have external power limitation selected in menu 7.4 and also written value 1 to register 3032.
There is no difference in power limitation on yes or no, validation fails with the same code.

Not sure what I'm overlooking. I'm on firmware 4.10.5 on Nibe and on v0.306.1 for evcc. I don't have any SG-Ready connections in the heatpump (no wiring).

[VallahDieWaldfee]

Is Modbus in your Heatpump activated? Double checked modbus ID and ip?

are you able to get the registers in other programs like home assistant?

[ArnoPW]

Yes, in Home Assistant everything is available and modbus is indeed available (I did also write value 1 to register 3032 successfully as stated in the explanation when adding the heatpump.

It always give me the following error when I validate:

chargeStatus: read failed: modbus: exception '1' (illegal function), function '4'

It makes no difference whether or not I enable power limitation

[VallahDieWaldfee]

But there’s no other client connected to the heatpump? Nibe only allows one modbus client

[ArnoPW]

I disabled the home assistant integration and waited a couple of minutes to be sure there is no other system using modbus. It gave the same error.