CAN stands for ' controller area network' and was primarily designed by the companies of Bosch and Intel for automotive internal use (autobus). But in the meantime 'CAN' proved itself as a reliable fieldbus in the automation section ,too. Like all other fieldbusses, too, CAN is based on the OSI 7-layer-model, but is only normed for the first and second OSI layers. The 'missing' application layer is defined by the layer 7 protocols like DeviceNet, SDS, CAL and the CANopen profile. The CAN bus is a serial bus system with equal access right for all participants. This means every device (Node) is able to transmit and to receive. the linear structure of the network keeps the bus system stil working even if one node is faulty.
CANopen is an open protokol standard for the CAN bus and was standardised in the automation by the so called "CAN in automation" (CiA). The protocol uses the CAN bus as transmission medium and defines the structures for network management, CAN-Identifiers, bus timing, the kind of data tranfer and application profile. This ensures the compatibility of differtent devices of different manufacturers.
By its good fault tolerance and effective fault recognition the CAN bus can be used under heavy interference conditions in industrial applications. By using of the frenzel & berg electronic CANopen devices, the user has a wide variety of possible solutions for I/O- and peripheral extension.
frenzel & berg electronic CANopen products:
PLC modules with CANopen: