Arduino-based Modbus RTU to Modbus TCP/UDP gateway with web interface. Allows you to connect Modbus RTU slaves (such as sensors, energy meters, HVAC devices) to Modbus TCP/UDP masters (such as home automation systems). You can adjust settings through web interface.
Allows you to connect your Modbus RTU slaves (such as sensors, energy meters, HVAC devices) to Modbus TCP/UDP masters (such as monitoring systems, home automation systems). You do not need commercial Modbus gateways. Arduino (with an ethernet shield and a cheap MAX485 module) can do the job!
Change settings of your Arduino-based Modbus RTU to Modbus TCP/UDP gateway via web interface (settings are automatically stored in EEPROM).
Screenshots of the web interface:
Get the hardware (cheap clones from China are sufficient) and connect together:
Download this repository (all *.ino files) and open arduino-modbus-rtu-tcp-gateway.ino in Arduino IDE. Download all required libraries (both are available in "library manager"). If you want, you can check the default factory settings (can be later changed via web interface) and advanced settings (can only be changed in sketch). Compile and upload your program to Arduino. Connect your Arduino to ethernet, connect your Modbus RTU slaves to MAX485 module. Use your web browser to access the web interface on default IP http://192.168.1.254 Enjoy :-)
https://en.wikipedia.org/wiki/Modbus
http://www.simplymodbus.ca/FAQ.htm
Feel free to use this sketch as a template for a web interface within your own project. Look into the main file (arduino-modbus-rtu-tcp-gateway.ino) for how settings are stored in and loaded from EEPROM during boot. Ethernet interface and Webserver is started via function in 01-interfaces.ino. All other functions related to the web server (reading from clients, sending pages to clients) can be found in separate files (04-webserver.ino , 05-pages.ino ). Feel free to adjust them.
The key to success is:
Big thanks to the authors of these libraries and tutorials!
The code was tested on Arduino Nano, Uno and Mega, ethernet chips W5100 and W5500. It may work on other platforms, but:
The default Ethernet.h library determines MAX_SOCK_NUM by microcontroller RAM (not by Ethernet chip type). So if you use W5500 (which has 8 sockets available) on Arduino Nano, only 4 sockets will be used. If you want to force the library to use 8 sockets, edit https://github.com/arduino-libraries/Ethernet/blob/master/src/Ethernet.h#L36
Not everything could fit into the limited flash memory of Arduino Nano / Uno. If you have a microcontroller with more memory (such as Mega), you can enable extra features in the main sketch by uncommenting: