Controller Area Network (CAN)

An introduction into the Controller Area Network

CAN is perfectly suitable for the area of industrial automation

1. Short introduction into the Controller Area Network

What is CAN?

CAN stands for Controller Area Network and networks control components, e.g. in a vehicle. The bus system handles the data change and the communication between different electronic modules. In cars, for example, the CAN bus handles communication between the controls in the cockpit and the engine.

Since when has CAN existed?

The CAN system revolutionised automotive electronics and fieldbus development in the 1990s. This modern two-wire bus system was developed by Robert Bosch GmbH in Germany between 1983 and 1986. Intel launched the first CAN controller generation on the market in 1987. Today there is the third generation, known as CAN XL, which enables direct Internet communication and considerably expands the range of applications.

2. The three CAN basis versions

First generation: CAN 2.0 CC or Classic CAN up to 1 Mbps (ISO 11898-1)

  • CAN 2.0 A ID11 Bit (standard format)
  • CAN 2.0 B ID29 Bit (advanced format)
  • ID stands for identifier as the first data packet of each transmission (type of content + priority + address)

Second generation: CAN FD and CAN FD light (FD = Flexible Data) max. 10 Mbps

  • CAN FD Light (ISO11898-1:2024)
  • One host with multiple slaves and a simplified protocol
  • CAN CC 2.0 A ID11 bit compatible
  • CAN FD (ISO11898-1:2015) Standard
  • CAN CC 2.0 ID11/29 bit compatible
  • CAN FD SIC transceivers (Signal Improvement Capability) support backward compatibility, hybrid network topologies and also higher data rates

Third generation: CAN XL (Extra Large) up to netto 20 Mbps (ISO11898-1:2024)

  • CAN ID11Bit
  • Scalable and basically downward compatible
  • Transceiver mode programmable (CC, FD, XL SIC, XL SIC Fast)
  • Co-existance of CAN FD and CAN XL in one network
  • Optional with Ethernet tunnel
  • VCAN max. 256 virtual networks
  • etc.

3. Various connector types at CAN

Female and male D-Sub 9 connector

Female and male M12 A-coded 5 pin (pin assignment)

Female and male 5-pin style "mini"

Female and male 5-pin style "micro" (M12)

Female and male RJ45

Female and male RJ10

4. CAN as field bus system

Fieldbuses are data networks used in industry for machine control and automation. They connect control computers such as PLC computers with actuators (e.g. presses, motors) and sensors (e.g. temperature sensors, reading devices). The CAN bus standard meets important requirements like real-time capability, data prioritization and error correction.

The CAN bus is frequently used in the automotive area, but there are a lot of other CAN field buses such as CAN open, NMEA2000, DeviceNet, and SAE J1939. All these base on the CAN standards and, furthermore, have additional specific features. These systems are designed for various applications in devices, vehicles and industrial equipments.

Examples of other CAN application systems

  • Factory automation / robotics (CANopen / DeviceNet)
  • Agricultural equipment (SAE J1939, ISOBUS)
  • Truck, bus, construction machinery (SAE J1939)
  • Building automation (diverse)
  • Medical devices (CANopen)
  • Marine electronics (NMEA 2000)
  • Aviation (ARINC 825)
  • Military (MILCAN)
  • Solar systems
  • Model making

5. CAN and the ISO standard

CAN bus has been already standarsised in 1993 by the ISO 11898. Since then, the organisation CAN in Automation (CiA) decides further specifications and submits they for standardisation at the ISO. The CiA is the central contact point for the cooperation and knowledge transfer round about the development of the CAN bus architecture. In this way, it is ensured that the basic versions as well as the CAN field buses are developed in high quality.

6. Insight in the CAN key technologies

The ISO/OSI model is a general standard reference model for network protocols. It is divided into seven firmly defined transmission levels (the so-called layers). Each layer has specific data transmission tasks, from physical hardware to software applications. The CAN bus covers layers 1 and 2. This includes the CAN protocol in the data link layer, which is controlled via the CAN controller, and the CAN transceiver, which acts as an interface between the cable and controller in the CAN physical layer. These two components are essential for the CAN bus architecture.

Fig. 1: ISO/OSI model (ISO 7498)
Fig. 2: CAN in ISO/OSI model
Fig. 3: CAN implementation
Fig. 4: CAN standards

Layer 1 / Physikal Layer: CAN Transceiver

The CAN transceiver as a transmitter and receiver module forms the device interface and transmits precisely synchronised data signals between the CAN controllers via the CAN bus cable.

Layer 2 / Data Link Layer: CAN Controller and CAN Protocol

Each CAN bus device contains the CAN bus controller and the protocol stack software (control software), which is responsible for monitoring and controlling the data transmission between the various CAN devices.

7. Delock CAN bus components

Delock offers CAN bus components that comply with current standards. You can choose from a variety of cables, adapters, splitter and terminators for different CAN field buses. An example is the standarsised connector M12 A-coded 5 pin which is specified for different CAN field buses. It shows that a DeviceNet cable can also be used for CANopen or other fieldbuses.

Pinout M12 5 pin connection plug A-coded

PIN Color CANopen DeviceNet NMEA SAE J1939
1 Shield Shield Shield Shield Shield
2 Red optional V+ V+ V+
3 Black CAN GND V- V- V-
4 White CAN_H CAN_H CAN_H CAN_H
5 Blue CAN_L CAN_L CAN_L CAN_L

FAZIT

The Controller Area Network (CAN) is a cost-efficient and robust communication system that enables the networking of various electronic devices. Major advantages of the CAN bus are its versatility and reliability in demanding environments, lower integration costs of standardized controllers and software compared to proprietary solutions, its scalability and the possibility of migration into existing systems.

CAN is fault-tolerant, which means that it can continue to function even if there are faults in the network. CAN also offers very fast response times for hard real-time applications. In addition to the automotive industry, CAN is also used in aviation, industrial automation and medical technology, where reliable data transmission is essential.

Product examples

Product image Delock item 60667

Item 60667
D-Sub 9 + M12 CAN bus splitter 35°

  • Connectors: D-Sub 9 pin male and female, M12 male and female A-coded 5 pin
  • Operating temperature: -40 °C ~ 80 °C
  • Dimensions (LxWxH): ca. 72 x 41 x 16 mm
Adapter for connection to a CAN / CANopen device. Can be used for industrial applications for connecting control units, sensors and actuators in automated systems.
Product image Delock item 60666

Item 60666
D-Sub 9 + M12 CAN bus splitter 90°

  • Connectors: D-Sub 9 pin female, M12 male and female A-coded 5 pin
  • Operating temperature: -40 °C ~ 80 °C
  • Dimensions (LxWxH): ca. 92 x 70 x 16 mm
Adapter for connection to a CAN / CANopen device. Can be used for industrial applications for connecting control units, sensors and actuators in automated systems.
Product image Delock item 60665

Item 60665
D-Sub 9 female to M12 male CAN bus splitter 180°

  • Connectors: D-Sub 9 pin female, M12 male and female A-coded 5 pin
  • Operating temperature: -40 °C ~ 80 °C
  • Dimensions (LxWxH): ca. 74 x 38 x 16 mm
Adapter for connection to a CAN / CANopen device. Can be used for industrial applications for connecting control units, sensors and actuators in automated systems.
Product image Delock item 66741

Item 66741
D-Sub 9 CAN Bus Adapter 120 ohms resistor

  • Connectors: D-Sub 9 pin male and female
  • Resistor: 120 Ω
  • Dimensions (LxWxH): ca. 34 x 27 x 16 mm
Adapter for connection to a CAN device. The 120 ohms resistor between pin 2 and pin 7 is used for bus termination and to ensure the integrity of the communication protocol.
Product image Delock item 66745

Item 66745
M12 CAN bus cable male to D-Sub 9 female

  • Connectors: M12 male 5 pin A-coded to D-Sub 9 pin female
  • Operating temperature: -20 °C ~ 80 °C
  • Length inkl. connectors: ca. 1 m
This adapter cable is suitable for various industrial applications, such as CANopen for machine control or NMEA 2000® for shipping.
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