Modbus on RB

Stage 1 : Testing ModBus Communication (RS485) using modpoll

Step 1: Connect the A & B of energy meter to A & B pin in RuggedBoard RS485 port respectively.

For demonstration purpose I have used Elmeasure LG+ 1119 meter. If you are having any other meter then you have to read the datasheet of the meter vendor and provide proper parameters.

Step 2: Download the modpoll ARM execulatble binary and save it into your work directory. To download the file click below.

Step 3: Save the following code in .sh format on your working directory and name is as mbpoll.sh

./modpoll.bin -m rtu -a 1 -t 4:float -r 159 -b 9600 -s 1 -P none /dev/ttyS2

The above script has the following components:

  • m : communication mode

  • a : Slave address

  • t : data types of the slave holding register

  • r : Start Reference

  • b : Baud Rate

  • s : Stop Bits

  • p : Parity Bit

  • SERIALPORT : Serial port node of the RS485

Step 4: Run the above code to test ModBus communication

sh mbpoll.sh

If everything is correct your code will run without any error. and you can proceed to next stage.