Dear Sir, I use AC500 model 572. I want to communication with my controller via modbus RTU. I use function code 22 ( COM_MOD_FCT22_TYPE) to write data. Is the function COM_MOD_FCT22_TYPE only for internet TCP modbus? Is it active on Serial Network ? Because my controller have only RS485 serial. I use control builder 501 version 2.3. I see library modbus only for TCPmodbus Can you support me? Can you provide example about it? Thanks & Regard!