Understanding MODBUS, TCPIP, M-BUS, LON, and KNX

Understanding the Different Types of Communication Protocols


MODBUS, TCPIP, M-BUS, LON, and KNX are different types of communication protocols used in building automation systems. In this article, we will explain what each protocol is, its history, benefits, features, components, and applications.


MODBUS is a serial communication protocol that was initially developed by Modicon (now Schneider Electric) in 1979. It is a simple, open protocol that is widely used in industrial automation and control systems. The protocol allows communication between devices connected to the same network, making it easy to monitor and control different systems remotely.

Benefits of MODBUS:

  • Easy to implement and configure
  • Simple and efficient communication
  • Low-cost implementation
  • Widely supported by different manufacturers

Features of MODBUS:

  • Master/slave architecture
  • Supports serial and Ethernet communication
  • Communication speed up to 115 kbits/s (serial) and 10 Mbits/s (Ethernet)
  • Supports multiple data types

History of MODBUS: 

MODBUS was initially developed for use with programmable logic controllers (PLCs). Its popularity grew as more manufacturers started adopting the protocol, and it became an industry standard.


Transmission Control Protocol/Internet Protocol (TCP/IP) is a suite of communication protocols used on the internet and other networks. It is a connection-based protocol that provides reliable, ordered delivery of data across IP networks.

Advantages of TCP/IP:

  • Reliable and secure communication
  • Supports large networks
  • Compatible with various operating systems
  • Provides built-in support for error detection and correction

Disadvantages of TCP/IP:

  • Complexity of implementation
  • High overhead due to built-in error detection and correction
  • Not suitable for real-time communication


Meter Bus (M-Bus) is a communication protocol that is widely used in metering applications. It is a low-power, low-speed protocol that enables communication between devices such as utility meters, sensors, and actuators.

Main Components of M-BUS:

  • Master device (e.g., data concentrator)
  • Slave devices (e.g., utility meters, sensors)
  • M-Bus physical layer (e.g., two-wire bus)

Meter Bus System: 

The Meter Bus system enables remote reading and control of utility meters. It allows for the exchange of data between meters and other devices using the M-Bus protocol.


Local Operating Network (LON) is a communication protocol used in building automation systems. It is an open protocol that supports multiple applications and devices. LON uses a peer-to-peer architecture, allowing devices to communicate directly with each other without the need for a central controller.


KNX is a communication protocol used in building automation systems. It is a standard platform that allows various building automation devices to communicate with each other. KNX was developed by KNX Association, a group of over 400 manufacturers and service providers.

KNX Members: 

Some of the notable members of the KNX Association include ABB, Siemens, Schneider Electric, and Philips.

KNX Applications:

  1. Lighting Control
  2. Heating, Ventilation, and Air Conditioning (HVAC)
  3. Shading and Blind Control
  4. Audio and Video Distribution
  5. Security and Access Control
  6. Energy Management
  7. Home Automation
  8. Building Automation
  9. Remote Control and Monitoring
  10. Metering and Monitoring

KNX Mobile Apps: 

KNX provides mobile apps that enable users to control and monitor their building automation systems remotely. The apps are available for both Android and iOS devices.

KNX Media: 

KNX supports multiple media types, including twisted pair, power line, radio frequency, and IP/Ethernet. This makes it suitable for various building automation applications.


Engineering Tool Software (ETS) is a software application used to configure and program KNX devices. There are four versions of ETS available: ETS Inside, ETS Professional, ETS Lite, and ETS Apps.

ETS Dongle: 

The ETS dongle is a USB device used to connect a PC or laptop to a KNX network. It provides a secure connection between the KNX network and the PC, enabling configuration and programming of KNX devices.

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Understanding MODBUS, TCPIP, M-BUS, LON, and KNX
Administrator December 22, 2023
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