0124-22 Modbus TCP Master

Example Projects > 0124 PiFace Digital > 0124-22 Modbus TCP Master

PiFace Digital as Modbus TCP master

This folder contains the source files for the demonstration project on using REXYGEN on the Raspberry Pi minicomputer with the PiFace Digital expansion board.

This example implements a Modbus TCP master for controlling a Modbus TCP slave device.


  • REXYGEN Runtime Core, RPiDrv and MbDrv modules must be installed and running on the Raspberry Pi.
  • SPI bus must be enabled on the Raspberry Pi
  • The Modbus TCP slave device must be available. It is supposed to have the IP address

Running the example

  • The *exec.mdl file is the project main file.
  • Open it with REXYGEN Studio, compile and download it to the target device.

Modbus TCP slave setup

In this example the Modbus slave has 8 output coils at addresses 0 to 7.

The Modbus master can use the commands FC05 (write single coil) or FC15 (write multiple coils) to manipulate the outputs (coils).

Adding signals, changing Modbus register mapping, changing IP address of the slave device

Go to Modbus TCP Master driver (MTM block) configuration and press "Configure" for Modbus configuration. Make sure to read the Modbus driver documentation (see below).


Additional information

  • Raspberry Pi is a trademark of the Raspberry Pi Foundation.
  • Visit the REXYGEN webpage for more information about the example projects and developing advanced automation and control solutions using REXYGEN.