Modbus RTU to TCP Bridge
December 1, 2022 ยท View on GitHub
A simple Modbus RTU Master to Modbus TCP Server Bridge that is done with off-the shelf parts utilizing the ESP-8266
Hardware
Specifications
- Current Requirements: ~30mA@12V
BOM
- ESP-8266 https://esp8266-shop.com/product/nodemcu-esp8266-esp-12e/
- RS485 Board https://www.waveshare.com/rs485-board-3.3v.htm or equivalent
- 3V3 DC-DC Regulator https://www.pololu.com/category/209/d24v5fx-step-down-voltage-regulators
- Wire, solder etc.
Schematic
The waveshare board has all the passive components and connector incorporated.
Software
Used Libraries
modbus-esp8266 v. 4.1.0 https://github.com/emelianov/modbus-esp8266
Configuration
Fill the setup config section with your values in the arduino file and you are good to go.
Known Limitations
- Only one TCP Client/Master is supported at the same time. Unpredicted behaviour on end application may occur if multiple TCP Clients make requests at the same time.
Notes
- A big thanks to Alexander Emelianov for helping with this project.
- If you like the project please star this repository and concider donating or becoming a sponsor.