How to set up data reception using Modbus Rtu?

Question

linux

I need to set up modbus. The master is a single-board computer on Linux, the slave is the modbus slave program (in the future, the kinco device will act).
Initially, I need to write my Master on Linux, but in order to check the operation of the devices, I installed the mbpoll program on Linux - b 9600 - c3 - r 1 - t 0 - a 1 -P none - m rtu at startup gives an error Read discrete output (coil) failed: Connection timed out I checked the connection, I can’t understand what is the error? If anyone knows how to make the same request in C++ I would be grateful (I use the libmodbus library).

Answer 1

Perhaps you need to give permission to the user to use the COM port
sudo usermod -a -G dialout