Date : March 30, 2024

Hey, this is Shaunak !

In this blog, I am carrying forward my previous work on the Modbus RTU Function Subset Implementation based on a Generic Library. I had tested this library on Cypress PSoC5 and TI Stellaris Launchpad Kit. This time I have tested it with Arduino Mega and Uno. 

Modbus is a data communication protocol widely used in industries. Click/Tap here to know more about it.

For this project, as a reference, I have referred the following document in order to understand its working :

The project implements 8 Modbus RTU Functions with a dedicated  C library that can be used in general. The 8 Modbus Functions are as below :

1. 0x01 : Read Coils

2. 0x02 : Read Discrete Inputs

3. 0x03 : Read Holding Registers

4. 0x04 : Read Input Registers

5. 0x05 : Write Single Coil

6. 0x06 : Write Single Register

7. 0x0F : Write Multiple Coils

8. 0x10 : Write Multiple Registers

The working of all the functions has been tested on a Modbus Master Tool called qModbus.

Download qModbus from Here 

Here is a document answering some common questions relevant to this project :

Click/Tap Here to get the Project as above from EmbVerse Github

Here is a video explaining the work in detail :

Note

Once this library is tested with qModbus and is ready to be implemented on field, a UART TTL to RS485 Two-way Converter Module is required because most of the microcontrollers do not support Modbus RS485 layer.