Controller Area Network (CAN) was initially created by German automotive system supplier Robert Bosch in the mid-1980s for automotive applications as a method for enabling robust serial communication. The goal was to make automobiles more reliable, safe and fuel-efficient while decreasing wiring harness weight and complexity.Since its inception, the CAN protocol has gained widespread popularity in industrial automation and automotive/truck applications. Other markets where networked solutions can bring attractive benefits like medical equipment, test equipment and mobile machines are also starting to utilize the benefits of CAN.
CAN OVERVIEW :
CAN PROTOCOL BASICS :
CAN OVERVIEW :
Most network applications follow a layered approach to system implementation. This systematic approach enables interoperability between products from different manufacturers. A standard was created by the International Standards Organization (ISO) as a template to follow for this layered approach. It is called the ISO Open Systems Interconnection (OSI) Network Layering Reference Model.
CAN PROTOCOL BASICS :
Carrier Sense Multiple Access with Collision Detection (CSMA/CD)
The CAN communication protocol is a CSMA/CD protocol.The CSMA stands for Carrier Sense Multiple Access. What this means is that every node on the network must monitor the bus for a period of no activity before trying to send a message on the bus (Carrier Sense). Also, once this period of no activity occurs, every node on the bus has an equal opportunity to transmit a message (Multiple Access). The CD stands for Collision Detection. If two nodes on the network start transmitting at the same time, the nodes will detect the ‘collision’ and take the appropriate action. In CAN protocol, a nondestructive bitwise arbitration method is utilized. This means that messages remain intact after arbitration is completed even if collisions are detected. All of this arbitration takes place without corruption or delay of the higher priority message.
The CAN communication protocol is a CSMA/CD protocol.The CSMA stands for Carrier Sense Multiple Access. What this means is that every node on the network must monitor the bus for a period of no activity before trying to send a message on the bus (Carrier Sense). Also, once this period of no activity occurs, every node on the bus has an equal opportunity to transmit a message (Multiple Access). The CD stands for Collision Detection. If two nodes on the network start transmitting at the same time, the nodes will detect the ‘collision’ and take the appropriate action. In CAN protocol, a nondestructive bitwise arbitration method is utilized. This means that messages remain intact after arbitration is completed even if collisions are detected. All of this arbitration takes place without corruption or delay of the higher priority message.
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