Hi,
thank you for the reply :). Yes I have a 120ohm resistor and the end of the line and I assume the USB to RS485 converter has one internally. I also tried to add one to the converter, but it didn’t change anything.
Meanwhile I switched from this modbus1 binding to the experimental modbus2 binding, which is mentioned in the community: Modbus openHAB2 binding available for alpha testing - #441 by zacofunny
With this binding it does work way better, but I still have an issue so solve…
So long
Sven