With the continuous improvement of industrial automation, the importance of industrial bus technology has become increasingly prominent. As one of the core technologies in the industrial field, the industrial bus plays an important role in achieving efficient communication and data exchange between devices. The industrial bus refers to a collection of public signal lines that transmit information and communicate with each other between modules. Under the control of the main device, the sent information is transmitted to a receiving device.

According to the location of the bus, the bus can be divided into external bus, internal bus and on-chip bus. Common external buses include RS-232, RS-485, USB bus, CAN bus, etc. common internal buses include HT bus, I2C bus, SPI bus, etc.common system buses include data bus, control bus, address bus, etc.

Commonly used industrial buses

CAN bus

CAN (Controller Area Network) is an ISO internationally standardized serial communication protocol. CAN bus is a serial data communication protocol developed by German BOSCH in the early 1980s to solve the problem of data exchange between many control and test systems in modern automobiles. It can use twisted pairs, coaxial cables or light guides. Fiber is used as a multi-master bus as the communication medium. Communication rate up to 1Mbps.

Ether CAT bus

Ether CAT (Ethernet for Control Automation Technology) is a high-performance industrial Ethernet communication protocol specially designed for real-time industrial control systems. It was launched by the German Beckhoff Automation company in 2003 and is an open international standard.

In an Ether CAT network, data is transmitted through a ring or linear network structure. Each slave device reads the data it needs and then immediately passes the data packet to the next slave. This process is called "processing on the fly".

ProfiNet bus

ProfiNet is an advanced communication system supporting distributed automation developed by Siemens and the ProfiBus User Association. Transplanting the master-slave structure of ProfiBus to Ethernet is an automation bus standard based on industrial Ethernet technology. It not only supports a variety of topologies to facilitate system integration and expansion, but is also compatible with existing Ethernet interfaces and protocols; not only can it realize real-time control of line bodies, but it can also provide data services to the Web and the cloud through TCP.

ModBus bus

The ModBus communication protocol was invented by Modicon in 1979 and was the earliest bus protocol used in industrial fields. There are multiple versions of the ModBus communication protocol, among which the more commonly used ones are ModBus RTU, ModBus ASCII and ModBus TCP.

Reference factors

According to the different needs of application scenarios, the following factors need to be clarified:

①Timeliness requirements: According to the timeliness requirements of information transmission during the production process, select an industrial bus with high-speed transmission characteristics. Some common high-speed industrial buses include EtherCAT, ProfiNet, and EtherNet/IP. These buses have the characteristics of low latency and high bandwidth, and are suitable for scenarios that require high communication speed.

②Data volume and real-time performance: When choosing an appropriate industrial bus, you need to refer to the data volume and real-time performance requirements. Some buses such as CAN and DeviceNet are suitable for scenarios with small data volume and low real-time requirements, while ModBus and ProfiBus are suitable for scenarios with medium data volume and high real-time requirements.

③Reliability and fault tolerance: Consider whether there are a series of risks such as interference and equipment failure in the industrial environment. For example, the ControlNet bus has strong fault-tolerant characteristics and is suitable for scenarios that require high reliability. Moreover, some buses such as EtherCAT and ProfiNet have automatic detection and automatic repair capabilities, which can provide reliable communication.

④ Flexibility and interoperability: Whether the system needs to communicate with multiple devices and devices from different manufacturers is also one of the factors that need to be considered. Some industrial buses such as ModBus and OPC UA provide good interoperability and device compatibility, and are more suitable for scenarios that require communication with multiple devices.

Process steps

Before choosing a suitable industrial bus, it is recommended to take the following steps:

① Demand research: comprehensively consider the production process, equipment requirements and other special needs, and clarify the specific characteristics of the required industrial bus.

②Market research: Understand in detail the characteristics, application scenarios, market shares, costs, etc. of various industrial buses. You can obtain information by reading relevant reports, participating in industry exhibitions, consulting professionals, etc.

③Vendor evaluation: Contacting various industrial bus suppliers will help to better understand the performance, technical support and other services of each industrial bus.

④Technical verification: Through actual verification and testing, compare the performance and reliability of different industrial buses in the system (industrial bus indicators, such as bus transmission cycle, clock cycle, operating frequency, bus bandwidth), and choose the best solution.


After selecting a suitable industrial bus, you need to pay attention to the following aspects:

①Device compatibility: Ensure that the device is compatible with the selected industrial bus and supports the corresponding communication protocol.

②Topology structure: According to the system requirements, select the appropriate bus topology, such as bus type, star type, tree type or ring type.

③Efficient maintenance: Understand the maintenance and troubleshooting methods of industrial buses, and rationally plan and manage industrial bus networks to ensure the stability and reliability of communication.

Finally, consider long-term planning and scalability when choosing an industrial bus to avoid frequent replacement and upgrades.

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