CANopen

CANopen in Industrial Automation

CANopen is based on CAN (Controller Area Network), which is a fieldbus standard developed for application in motor vehicles. This standard is popular in Europe and grows in popularity in North America and in Asia.

CAN in Automation (CiA) is the organization responsible for administrating fieldbus standards. CiA was founded in 1992 and is a coalition between users and manufacturers whose products are based on CAN.

Here you can find our products which are compatible with CANopen

How does CANopen work?

Within the ISO/OSI layer model the CANopen protocol is found in layer 7, which is the user layer. CAN is responsible for layer 1 and 2 of the ISO/OSI layer model. Communication is done via telegrams. Process as well as device data may be transmitted. Transmission of alerts (emergency) is possible as well.

CANopen-Topology

CANopen-topology is generally set up as a line structure. Branches are possible. The network may be expanded by using repeaters and bridges in the amount of knots. CANopen-IO-devices are available to include sensors and actuators.

The master is responsible for network management according to the fieldbus standard. The assigned slaves may adopt the following conditions:

• Initialization
• Pre-operational
• Operational
• Stopped

While in operational state a slave device may send and receive.

Object Directory, Communication Profile, Device Profile

Each device has an object directory. It contains the objects as well as data types of the communication profile and the device profile. Pre-defined device profiles are available in CANopen for device types typical in industrial automation. Devices may be exchanged regardless of manufacturer if they have the identical device profile.

Data exchange in accordance with the producer-consumer-model is supported by the fieldbus standard. PDO (Process Data Objects) are used for transmission. SDO (Service Data Objects) are used for transmission of messages unlimited in length. Data is transmitted in a point to point connection.

Sensors and actuators may be connected in the control cabinet or in the field. A sufficient standard of CANopen-IO-modules is the requirement for this use case.

CANopen Cable

CANopen cables are available in all sorts of configuration. You may get a pre-configured version or an open end cable. The bus cable has to be a CANopen cable. A bus length of up to 40m requires a CANopen cable with a core-cross-section of 0.25 to 0.34.

Picture CANopen cable, shielded, 2× 0.25 + 2× 0.34 mm²

Shielded cables are recommended.

CANopen Connectors

T connectors are used to connect slaves. Slave devices may be plugged directly into the T connector. Alternatively, a short derivation cable can be used.

Power Supply via CANopen Cable

24 V power supply for connected devices is supported by the fieldbus standard. Additional cores for power supply are a requirement for the CANopen cable.

Each end of the CANopen cable should be sealed off, using a bus termination plug.