Modbus RTU Master With Arduino Via RS232 : 3 Steps - Instructables
Comunicación RS485 con Arduino
RS485 MODBUS Serial Communication using Arduino UNO as Slave
Ebyte LoRa E32 per Arduino, esp32 o esp8266: libreria – 2 – Renzo Mischianti
GitHub - andresarmento/modbus-arduino: A library that allows your Arduino to communicate via Modbus protocol, acting as a slave (master in development). Supports serial (RS-232, RS-485) and IP via Ethernet (Modbus IP).
Il protocollo MODBUS con Arduino - Video 314 - YouTube