0122-25 Modbus TCP Slave
Example Projects > 0122 UniPi 1.1 > 0122-25 Modbus TCP Slave
UniPi as Modbus TCP slave
This folder contains the source files for the demonstration project on using REXYGEN on the Raspberry Pi minicomputer with the UniPi extension board.
In this example the UniPi is used as a Modbus TCP slave to allow integration in complex or hierarchical control systems.
Prerequisites
- REXYGEN Runtime Core, RPiDrv and MbDrv modules must be installed and running on the Raspberry Pi.
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 registers
Modbus holding registers are used for data exchange. Use the Read Holding Registers command (FC=03) for reading the status of UniPi inputs and the Preset Multiple Registers command (FC=16) to manipulate the outputs.
UniPi input signals
| Register No. | Meaning | Data range |
|---|---|---|
| 0 | Digital inputs (LSB=I01) | 0..4095 |
| 1 | Analog input 1 (0..10V, 16-bit) | 0..65535 |
| 2 | Analog input 2 (0..10V, 16-bit) | 0..65535 |
UniPi output signals
| Register No. | Meaning | Data range |
|---|---|---|
| 2048 | UniPi relays (LSB=relay 1) | 0..255 |
| 2049 | Analog output (PWM on pin 18) | 0..1023 |
Adding signals and changing Modbus register mapping
Go to Modbus TCP Slave driver (MTS block) configuration and press "Configure" for Modbus registers configuration. Make sure to read the Modbus driver documentation (see below).
Documentation
- Press F1 for help on the selected function block in the REXYGEN Studio.
- Getting started with REXYGEN and UniPi board (Raspberry Pi)
- RPiDrv - Raspberry Pi driver (including PiFace Digital, UniPi v1.1 Intellisys PIO)
- MbDrv - Modbus driver
- Function blocks of REXYGEN
- REXYGEN Studio User Guide
- Complete documentation of REXYGEN
Additional information
- More info about the UniPi board can be found at unipi.technology.
- 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.