As ModBus is used in industry, and I have Arduino UNO, I want to used it, but it's not definitive. But it's not necesary Modbus TCP or Arduino UNO. I must use Codesys+Raspberry like PLC and Arduino like controller. With sensors, mini conveyor belt, alarms and that kind of things.

I try to create a 'micro' automatized factory, for educational purpose. This is very interesting and help me a lot, thank you, dou you know other library? I'm thinking on Modbusino.h but not support Coils functions, and I think that I prefer have it. It's designed to be used on ARM based Arduinos (which have much more RAM). You shouldn't use the ArduinoModbus library on AVR Arduinos as it wastes too much memory. Yes, I need a Raspberry as Client, and Arduino as Server. I have a shield ethernet for Arduino, sorry for not mencion it. Thanks for your answer only an UNO you cannot because the UNO doesn't have any network interface. What is the Arduino expected to do in your setup? You told us what you think is a (the best?) way technically (Modbus TCP) but there might be better options depending on the use case. Design HMI screens in two different software. Learning how to use Modbus TCP with multiple equipment. Have someone any idea how configure arduino modbus for control it via PLC raspberry? Arduino Uno / Nano / Leonardo / Micro Arduino Mega / Due Arduino Nano Every / IoT / BLE Arduino RB2040 Connect Arduino Mkr / Zero / WiFi Arduino Pro. Skills you will learn in this course: Arduino Integration with CodeSys Soft PLC systems. Modbus RTU has a master and slaves but Modbus TCP has a client and servers. The terminology of Modbus TCP is different to Modbus RTU.

I believed that I could configure Arduino as a ModBus slave (general), but reading the documentation I dont sure how make it. Using only an UNO you cannot because the UNO doesn't have any network interface. I read how to use this on Codesys, but my doubt is: how its the code that i must put on Arduino UNO, I'm reading ArduinoModbus.h documentation and ModBus Protocol (of ) but I'm not sure. I have read and investigated, and I see that one of protocol that i can use for this is ModBus TCP/IP.

Codesys Arduino