What is a CAN bus system ?

The use of the CAN bus system within the automotive sector allows the interconnection of groups of electronic components like control units or intelligent sensors, for instance the steering angle sensor. The abbreviation CAN stand for Controller-Area – Network.

The subsequent advantages for the general system, which is that the vehicle:

• Of knowledge between the control devices takes place on a homogeneous platform, called a protocol. The CAN bus is a sort of “data superhighway”.
• Systems integrating several control devices like for instance the ESP are often realized in economic conditions. within the sort of optional equipment are often easily achieved.
• The CAN bus is an open system which will be adapted to different means of transmission, like copper cables or fiber optic cables, for instance.
• The diagnosis of the control devices is administered via the K cable. The vehicle already carries out a partial diagnosis itself via the CAN bus (e.g. at the bag inflatable and door control unit).
• Diagnosis of various systems via several control units are often administered simultaneously.

Caractéristiques principales

Many individual modules are connected in parallel on the CAN bus system. the planning of the general system must therefore meet the subsequent criteria:

• High security: transmission faults of internal or external origin must be detected with a high level of security.
• High availability: within the event of an impact device failure, the remainder of the system should, if possible, still be operational so as to permit the exchange of data .
• High data density: the various control units have precisely the same status in the least times. The control devices thus have an equivalent data. within the event of a failure at one level or another of the system, the knowledge is transmitted to all or any connected devices.
• High transmission speed: the info exchange between the varied connected devices must happen very quickly, if possible in real time. Signal transmission over the CAN bus system is currently administered digitally using copper cables.

This guarantees secure transmission at a maximum speed of up to 1000 Kbits /s (1 Mbit / s).

Due to different experiences regarding signal iteration rate on the one hand and therefore the resulting data volume on the opposite hand, the CAN bus system is subdivided into 3 systems:

• Propulsion CAN bus (High-Speed) with 500 Kbits /s (almost in real time)
• Comfort CAN bus (Low-Speed) with 100 Kbits /s (lower time requirements)
• Infotainment CAN bus (Low-Speed) with 100 Kbits /s (lower time requirements).