I am currently attempting to communicate via Modbus TCP with a Schneider PM 5063 Power Meter. I need to read Holding registers from 2700 to 3100. I can successfully read registers below 2998, but with Codesys, I am unable to read beyond register 2999. When I try using a Modbus simulator (Modbus Poll), I am able to read registers greater than 2999. I have tried everything, but have not been successful. I am using Codesys Version V3.5 SP19 Patch 7. The firmware on the PLC is: FW28.
Since the parameter size is 2 words, could it be that you are reading the parameter at the wrong offset? Schneider modbus addressing is usually 1-based, so perhaps the offset for register 3020 in CODESYS should be 0x0BCB. Have you tried this?