CAN communication system

Abstract

The invention provides a CAN communication system. The CAN communication system of the invention has the beneficial effects that: conventional twisted pairs are replaced by optical fibers, and CAN transceivers are replaced by receiving pins and transmitting pins in a CAN controller, thereby solving the problem that the twisted pairs are used by conventional CAN node equipment to achieve interconnection, a data transmission distance is affected by an electromagnetic environment where a bus locates and a parasitic capacitance between cables, and the data transmission distance is limited, and enabling the communication distance from the CAN controller to node equipment to reach more than 200m; in addition, communication of other modules can not be affected by damage of any one CAN concentrator at a bottom layer, and each first CAN concentrator can be controlled separately from a second CAN concentrator.

Description

technical field [0001] The invention relates to the technical field of CAN communication. More specifically, it relates to a CAN communication system. Background technique [0002] CAN is a field bus that uses a non-destructive bit contention mechanism to realize serial multi-master communication. Due to the advantages of strong anti-interference ability, short message, good real-time performance and low networking cost, CAN bus is widely used in industrial automation sites and automotive parts control with harsh environments, large electromagnetic radiation, and high reliability requirements. field. The most commonly used CAN bus physical layer transmission medium is twisted pair. ISO11898-2 defines the high-speed CAN bus physical layer standard with twisted pair as the medium. In the CAN bus, the highest speed that the network can achieve is related to the size of the bus. For example, when the cable length is not greater than 40m, the highest rate that can be realize...

AI Technical Summary

Problems solved by technology

In actual use, the following reasons will cause the decline of the highest achievable rate: too many nodes connected to the bus cause bus parameter mismatch; the overvoltage and overcurrent protection circuit installed on the node causes bus parameter mismatch; The geographical distribution is too large, and the cables that are too long cause bus parameter mismatch

In addition, when the working environment of the bus is too harsh, such as when the common-mode potential difference between nodes exceeds the maximum value allowed by the physical layer transceiver device, the bus cannot work normally. Traditional CAN node devices use twisted-pair interconnection data transmission distance is limited by the bus Due to the influence of the electromagnetic environment and the parasitic capacitance between the cables, the data transmission distance is limited, the longest is only about 40 meters, so there are many restrictions

Images