The CAN bus (Controller Area Network) is one of the classic field buses. It connects the individual participants with each other in a control structure. It has been on the market since 1986 and is therefore a proven and very robust communication technology. Instead of many dedicated analog and digital signal lines, the CAN bus uses a two-wire cable for digital data transmission. System components such as control devices, sensors and actuators can be connected to this cable either directly or via additional distribution nodes. The maximum number of connectable system components depends on the driver modules. It is possible to connect 32, 64 or up to 128 nodes per CAN bus line.

The data transmission is done via two wires, which are called CAN_High and CAN_Low. A CAN network must be assigned an identical transmission rate for all participants. During data transmission in a CAN bus, no receivers (nodes) are addressed by a transmitter. In principle, each message is sent to all nodes simultaneously and is identified by a unique "identifier". This identifier also determines the priority of the message. All nodes in the CAN network continuously listen for messages and, on receipt of a message, check whether the data is relevant for them using the identifier. Messages can thus be received and evaluated by several nodes simultaneously. Such a message is called a "frame". There are different types of frames according to their job. A distinction is made between data, remote, error and overload frames.

Different protocol types are available, which define the use of identifiers for certain types of messages and the format of the data bytes. The best known protocols relevant for mobile machinery are CANopen, J1939 and ISOBUS.

By using the CAN bus with its two-wire cable, time and weight can be saved during installation and commissioning. The number of cables is significantly reduced. This also eliminates sources of error during connection and maintenance. Cost for material and set-up effort can be reduced.
The diagnosis and maintenance of control systems is simplified, as the device states are logged and stored. In addition, the CAN bus offers high data security and real-time capability.

CAN-Bus Fluidlexikon

Suitable HAWE products: