Modbus RTU communication with custom Device



  • Hello,

    i want to read Sensor Data and Control a Stepper connected to an Arduino via Modbus.
    Currently only a photoelectric barrier is connected to the Arduino.
    The Slave Id for the Arduino is 10 and the Address for the barrier is 99.
    Successfully testet the communication using mbpoll like so:
    mbpoll -a 10 -b 9600 -P none -t 1 -r 100 -c 1 /dev/extcomm/0/0

    Followed this Tutorial: https://www.unipi.technology/news/plc-programming-3-working-with-external-peripherals-using-modbus-360
    My Modbus Read Node does only show "reconnecting after 1000 msec."

    Hopefully someone can help me as this is my first Project with Node-RED and Modbus![alt text](image url)



  • Seems like the problem was a bad Connection or so.
    Testet something else and had to reconnect the rs485 wires and now it works.
    Bit weird that mbpoll worked without a problem...


Log in to reply