Components of CAN stations

In order for a CAN station to be connected to the CAN bus, a bus connection must be available. This bus connection consists of three assemblies:

• Transceiver
  The transceiver is connected directly to the bus line and ensures that the specified voltage is held on the bus line. Additionally it protects the CAN station from voltage surges.
• CAN controller
  The CAN controller is connected to the transceiver and receives from it the signals of the bus line. It filters out data irrelevant for its CAN station and sends only the relevant data along for processing. In addition it ensures that the CAN protocol is held during transmission of data. It is in the position to detect errors in the bus and to react appropriately.
• Microcontroller
  The microcontroller has a processing program and uses this to evaluate the data which it receives from the CAN controller. It can inquire about this from the connected sensor system and control the actuators. The type of sensor system and actuator system is dependent upon the respective area of application. So, for example, an engine control unit requires different sensors than a control unit for the ABS.

In practice the three components are placed entirely or partially on one microchip. This saves space and costs.

In automobiles such bus connections are integrated into the control units so that they are CAN compatible. The control unit is also directly connected to the bus system.