The importance of communication technology in modern industrial and electronic systems cannot be overstated. Among them, CAN (Controller Area Network) bus, as an efficient and reliable communication standard, has been widely used worldwide in many fields such as automobile, industrial automation, medical equipment, aerospace and agricultural machinery since it was developed by German Bosch in the early 1980s. This article will introduce the principle and characteristics of CAN bus and its application in various fields.

The origin and development of CAN bus

CAN bus was initially designed to solve the communication problems between electronic systems within automobiles. Prior to the 1980s, with the rapid increase in the number of electronic devices in automobiles, such as anti-lock braking systems (ABS) and air bag control systems, these systems needed to exchange information efficiently. However, traditional point-to-point wiring not only increased complexity but also manufacturing costs. by introducing the CAN bus, Bosch enabled the electronic control units (ECUs) in a car to exchange data efficiently and reliably over a common network.

In 1993, CAN bus became the international standard ISO 11898, which not only laid the foundation for the global deployment of CAN, but also facilitated the expansion of its applications in different industries. The original CAN standard (later known as CAN 2.0 or Classic CAN) supported data transfer rates up to 1 Mbps for high-speed communication scenarios. In order to accommodate application scenarios with higher requirements for low speed and fault tolerance, extended versions of CAN were later developed, such as CAN 2.0B and CAN with Flexible Data Rate (CAN FD).CAN FD increases the length of the data field to support greater data throughput, which is suitable for higher-speed data transmission requirements.

Principle and characteristics of the CAN bus

CAN bus is a serial communication bus based on the message broadcasting mode, which utilizes multi-master control so that any node can send a message to any other node on the network at any moment without waiting for the bus to become idle. This mechanism makes the CAN bus highly real-time and flexible.

When two or more nodes send information to the bus at the same time, the CAN bus uses a non-destructive bus arbitration mechanism to decide which node can continue to send data based on the node's priority. This arbitration mechanism ensures reliable data transmission and avoids bus access collisions.

The CAN bus also supports error detection and processing, using the CRC (Cyclic Redundancy Check) algorithm for error detection. When an error is detected, an error flag is sent to notify other nodes to stop sending data and to handle the error. This mechanism further enhances the reliability of the CAN bus.

In addition, the CAN bus has the following features:

Physical and Data Link Layer Standards: The CAN bus standard only specifies the physical and data link layers, requiring the user to customize the application layer. Different CAN standards differ only in the physical layer.

Flexible network topology: CAN bus supports a variety of network topologies, such as bus type, star type, ring type and so on.

Good electromagnetic compatibility: CAN bus can work normally in harsh electromagnetic environments.

Support multiple communication rates and number of nodes: CAN bus supports multiple communication rates, such as 1Mbps, 500kbps, 250kbps, etc., and generally can reach dozens or even hundreds of nodes.

CAN bus application fields

CAN bus is most widely used in the automotive field, and has become a standard solution for communication within vehicles to connect key components such as engine control units, sensors, and anti-lock braking systems. It also plays an important role in industrial automation for robot control, production line monitoring, etc. The reliability and real-time nature of CAN bus makes it ideal for these applications.

CAN bus is also widely used in medical equipment for data transmission and control. For example, in operating rooms and intensive care units, various medical devices such as monitors and ventilators can share and coordinate information via CAN bus. In addition, CAN bus is also widely used in aerospace, agricultural machinery and other fields. For example, in an airplane, CAN bus can be used to connect key equipment such as navigation system and control system to realize real-time transmission and sharing of information.

Looking to the Future

Despite its success in a number of fields, CAN bus is facing new challenges with the development of Internet of Things (IoT) technology and the need for higher data rates. To address these challenges, engineers are exploring new technologies such as time-sensitive networking (TSN) and CAN XL, designed to increase bandwidth and real-time performance to support more complex networks and applications.

Overall, CAN bus has been widely used worldwide as an efficient and reliable communication standard. With the continuous progress and innovation of technology, the future of CAN bus is still full of opportunities and challenges. We have reason to believe that CAN bus will continue to play an important role in industry, providing strong support for communication needs in various fields.