Why I cannot find the unit ID on "Tab ‘ModbusTCP Slave Device - General’"? Is it because I'm using the latest version of the modbus TCP slave library? Without unit ID setting available, I have to set device ID to 255 when using modscan or other test softwares. Or is there any to ignore the unit ID for the modbus TCP slave device?
Hi mmxfan, Did you find a solution as I have the exact same problem with the removal of the unit ID
not a chance.
With SP17 (March 2021 maybe?) the modbus TCP slave device will ignore the unit-ID, if a serial gateway is not enabled. So you will be able to use any unit-id you like. Currently Unit-ID 0 (really a broadcast to all addresses) and Unit-ID 255 work.
I am curious, do you have some modbus-master device, which cannot use unit-id 0 nor 255?
Sorry, should have posted. The issue ended up being that in Modbus TCP Slave I/O Mapping I had to change the Bus Cycle Task to "Task" and the Always Update Variables to "Enabled 2 (always in bus cycle task)". Everything kick in at that point
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