If I remember correctly, the LAMBDA service had to set the write permissions to writable registers once.
Edit: Modbus is enabled by default, but read-only! If you want to write, the service technician must enable it.
Thanks for confirming.
This is soooo German. Yuck.
I asked to enable the E-Manager by mail to the lambda-support. Within one day they configured it to
E-Meter Kommunikationsart: ModBus Client
E-Meter Messpunkt: E-Eintrag
Might be they allowed writing automatically when I asked for using the E-Manager.
Regarding limiting heating: You might try to switch off the heating circuit(s) writing 0 to register 06: Operating mode. This register ist RW. I never tried it, might be interesting.
If you use the lambda heating water for domestic use you could try to lower the Maximum Boiler Temperature (Register 50).
Is anybody able to test the solar part? I have added it to the binding but have no possibility to test it.