I have an IR33 Carel controller and I am trying to send the following commands to it.
02 31 3f 03 37 35 --> all in hex.
Controller responds with 00 only.
This is at 19200, no parity one stop bit. I am thinking the on board 4 pin header is actually UART lines. i measure and I see both pins are pulled up high.
I am not using the RS485 IROPZ48500 adaptor. I am interfacing direct to the controller using a USB to UART coverter plug.
Am i sending the correct commands? Or IROPZ48500 sends entirely different frame altogether?