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 RISH LM-1360 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.

17KB

modpoll.bin

modpoll.bin

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 -r 1 -c 4 -t 4:float -b 9600 -d 8 -n 4 -p none /dev/ttyUSB1

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.