Research On Multi-node Data Acquisition System Based On Embedded Technology And CAN-bus

CAN(Controller Area Network)bus has a good data communication function to make it widely used in modern industrial control systems,its unique non-destructive arbitration provisions allows the system to quickly handle some high-priority tasks,and may cause some low-priority message transmission delay in the data acquisition system.This paper studies how to plan the transmission process of packets in CAN bus multi-node data acquisition system,improve the fairness and real-time of message transmission,and achieve the purpose of collecting node data in real time.Firstly,the existing time-triggered scheduling strategy is less flexible and does not consider the problem of random information scheduling strategy.This paper proposes a dynamic scheduling algorithm based on time triggering,which improves the time structure of matrix period in TTCAN protocol and adopts two triggering methods to schedule random information,improve the flexibility of system operation and the response of low priority nodes time.Secondly,the dynamic scheduling algorithm is used to establish the matrix period according to the periodic information parameters in the vehicle control system.Then the simulation model of the dynamic scheduling algorithm is constructed and compared with the random information scheduling strategy in the static scheduling algorithm of TTCAN.The results show that the dynamic scheduling algorithm can distribute the network resources evenly and improve the real-time performance of information transmission on the network.Finally,a CAN bus multi-node data acquisition system based on embedded technology is established.Using the multi-task processing mechanism of the main node to manage the CAN network system communication scheduling,combined with the dynamic algorithm implementation and data transmission format,etc.,to develop CAN bus application layer communication protocol,And then use the SQL database technology and serial communication technology to design the host computer data resource storage system,verify the multi-node data acquisition system function,to achieve the desired design goals.