Modbus-TCP Restrictions for Bridges

is there any real reason why we can’t define several modbus-tcp bridges to the same ip/port but with different id?
Let’s take the SMA inversters. Polling register 42109 with id 1, delivers 4 register value containing the serialnumber, susyid and the id for the regular modbus-tcp communication. In my case it’s unit id 4, which is the id I use currently in openhab.
Additional it’s possible to use id 3 for special communication. But I can’t use it, because openhab is resticted to one id per ip/port combination. Why are openhab’s modbus-tcp bridges restricted in that way? I can’t imagine any reason for that.

Is there any chance that this can be changed?


You can define the bridge twice with the same ip/port but different IDs. Doesn’t this work for you?

No, I get this error

Endpoint ‘ModbusIPSlaveEndpoint [address=SMA3010987xxx, port=502]’ has conflicting parameters: parameters of this thing (modbus:tcp:e6b17d1526 ‘Modbus TCP Slave’) are different from some other thing’s parameter. Ensure that all endpoints pointing to tcp slave ‘SMA3010987xxx:502’ have same parameters.

I have to correct - it’s working.
They had different Reconnect again after values. After aligning, worked.

Thanks for the hint