Modbus sniffer?

hi all, i am trying to implement a modbus sniffer. you will wonder why. very simple. I have a heat pump (slave) that communicates in modbus with its lcd panel (master). I would like to fetch the machine data without adding a second master to the modbus network. I then bought a modbus tcp converter and put it as a client to the tcp listner on nodered. I see a lot of traffic coming. Do I find any projects ready to implement it? Can anyone help me? I would just like to read the answers the machine sends to the panel! thanks a lot

Hi, have you bit a tcp/serial converter? If yes...the serial si RS485? If yes...you must link a cable in parallel at the serial. If there Is a terminarono resistant you must put this at last device...(your converter.).