MODBUS And Profibus Small introduction

Modbus is a widely used communication protocol in the industrial automation sector. It was originally developed by Modicon in 1979 and has since become a de facto standard for connecting devices in supervisory control and data acquisition (SCADA) systems.

Modbus TCP/IP and Modbus RTU are two different variants of the Modbus protocol, and they differ in terms of their physical and network layers.

Modbus TCP/IP:
Modbus TCP/IP is a variant of the Modbus protocol that uses TCP/IP (Transmission Control Protocol/Internet Protocol) as its transport layer. It enables communication over Ethernet or the Internet. Here are some key characteristics of Modbus TCP/IP:
Transport Layer: Modbus TCP/IP uses TCP/IP as the transport layer protocol. TCP ensures reliable and ordered delivery of data packets over an IP network.
Physical Connection: Modbus TCP/IP requires an Ethernet connection, usually using an RJ45 connector, to establish communication between devices.
Network Topology: It operates on an Ethernet network, which can be structured as a local area network (LAN) or a wide area network (WAN).
Addressing: Modbus TCP/IP uses IP addresses to identify devices on the network. Each device has a unique IP address, and communication is established by sending Modbus function codes over TCP/IP packets.
Modbus RTU:
Modbus RTU is a variant of the Modbus protocol that uses serial communication for data transmission. It is typically implemented over RS-485 or RS-232 physical interfaces. Here are some key characteristics of Modbus RTU:
Transport Layer: Modbus RTU uses a binary protocol for communication. It does not rely on any specific network or transport layer protocol like TCP/IP.
Physical Connection: Modbus RTU uses serial communication, typically implemented over RS-485 or RS-232 interfaces. RS-485 allows for multi-drop connections with several devices connected in a daisy-chain fashion.
Network Topology: Modbus RTU is commonly used in point-to-point or multi-drop configurations, where multiple devices are connected in a bus-like topology.
Addressing: In Modbus RTU, devices are addressed using unique IDs rather than IP addresses. Each device on the bus has a unique ID, allowing for targeted communication with specific devices.
In summary, Modbus TCP/IP operates over Ethernet networks and uses TCP/IP for reliable communication, while Modbus RTU operates over serial interfaces like RS-485 and uses a binary protocol for data transmission. The choice between the two variants depends on the specific requirements of the system, such as the network infrastructure and the type of devices being connected.


Modbus is like a simple language that allows different devices to talk to each other and share information. Imagine you have two friends who don't speak the same language. Modbus helps them communicate by providing a common way for them to understand each other.

Profibus is similar to Modbus, but it's a bit more advanced. It's like a special language that allows many devices to communicate with each other in a big network. Imagine you're in a classroom with many friends, and you all want to play a game together. Profibus is like the teacher who helps you organize the game and make sure everyone knows what to do.

So, to sum it up, Modbus is a simple language that helps two devices communicate, while Profibus is a more advanced language that helps many devices in a network communicate and work together.