Nam Nam's ESP32-Powered Modbus Board Provides Easy RTU, TCP/IP Connectivity
Got a need to do some Modbus talk in your automation projects? This compact DIN-mountable board has what you're looking for.
Vietnamese hardware engineer Nam Nam has launched an Espressif ESP32-powered gadget designed to make easier to work with Modbus RTU and TCP/IP devices — complete with wired Ethernet and Wi-Fi connectivity.
"This is device support[s] read/write [over] Modbus RTU, Modbus TCP/IP," Nam Nam explains of the compact development board. "Upload code via USB Type-C. Use it when you need to connect with PLC [Programmable Logic Controller] or read a sensor device [has] standard Modbus RTU or TCP/IP. The device is compact and works stably in industrial environments."
The heart of the build, brought to our attention by CNX Software, is an Espressif ESP32-WROOM-32D, giving it two 32-bit Tensilica Xtensa LX6 processor cores running at up to 240MHz, 520kB of static RAM (SRAM), and 512kB of flash storage. To this, Nam has added an SPI-connected Fast Ethernet wired network connection, to serve as an alternative to the module's on-board Wi-Fi and Bluetooth radios.
The board's form-factor is designed to fit in with DIN-rail installations, and there's support for a fan mounted over the microcontroller module if it's expected to run under load in high environmental temperatures. Sample code published for the board includes reading Modbus data via RTU or TCP/IP, acting as a Modbus server over both connections, automatic switching between Wi-Fi and wired EThernet connections, MQTT communications, over-the-air firmware updating, use of the watchdog timer, and a deep sleep mode for power saving.
The Modbus board is available on Nam's Tindie store at $35; example code is available on GitHub under an unspecified license.