The Design Of Communication Network Of The Measurement System Based On CAN Bus

As one of the most promising fieldbus currently, The main characteristic of CAN bus is the have good real-time performance in communication, high reliability, and cost-effective outstanding.So the CAN bus are gradually becoming a hotspot of automation development. it's application areas has been expanded gradually from car bus to many industrial control areas.This paper mainly studies on the communication network of measurement system based on CAN bus. According to the actual needs of the measurement system,the network composed of master node and some data acquisition nodes in composition,the network must possess high real-time and high reliability, Therefore we maked bus redundancy design on the hardware for the all nodes in the network, Meanwhile we maked the redundancy design for the master node which has the most key role. At the same time, we designed the application layer protocols based on the CAN2.0 B for the communication network, The protocols mainly includes formulate the data frame'ID format,the real-time communication mechanism and redundancy automatic switching mechanism. All of the nodes in network in accordance with the protocols, may achieve the real-time communication and function of automatically redundancy switch when the bus or the master node have malfunctioned. Because of CAN bus characteristic of oneself, communication distance is limited, node number only 110 at best. In order to expand the CAN bus communication distance, increase node number of the network, and achieve data exchange between the high speed and low speed networks,we design the CAN bus repeaters,this greatly increased the expansibility of the network. In order to check the communicate data of the CAN bus network, this paper designed the CAN network monitor,it can achieve real-time monitoring for the network.They together formed a fully CAN bus communication network. The system can apply immediately in the industrial field areas.After the system are completed,we tested to the communication system. Test results show that: The communication network of measurement system based on CAN bus can run a good, stable performance, and it can reach the expected requirements.