TUTORIAL: How To Use RS-485 TTL MODBUS - Arduino Controller Module (Part 1/2 - Wire Up) Solar - YouTube
Stepper motor driver with modbus - How to use it | PoLabs.com
Using Arduino UNO to control a stepper motor via RS485 - Microcontrollers - Arduino Forum
GitHub - CloudHead84/Modbus-Stepper-Controller: Step/Dir Controller based on teensy. Acts as a Modbus tcp slave, so a modbus master is needed for the setup. the master will need a library issuing different commands
Arduino - Modbus | Arduino Tutorial | Arduino, Tutorial, Use case