The Research And Implement Of In-Circuit Upgrading Technology On Distributed Control Systems

Along with field bus's successful performance during spread and application, distributed control systems had become an open, absolutely dispersed field bus control system, with each child control system become an embedded system which is intelligentized and also capable of communicating with others to some extent. But on the other side a command for upgrading system codes according to local field was put up. The development of semiconductor and embedded technology had promoted advance of In Circuit Programming and Debugging technologies, which were apt to upgrade embedded systems when they were under experiment environment but not suitable for distributed control system's renewal.In order to abate the inconvenience in upgrading distributed system, combined with embedded system's specialties, a new kind of remote in-circuit programming technology via field buses had been brought forward on base of analysis of In Circuit Programming principles. The article detailed the essence of In Circuit Programming Technology via field bus, both scheme's feasibility and compatibility with other elements in whole system after upgrading were demonstrated, and also system structure and work flows were described. The technology showed no special request on hardware and could work well based on field bus control system's hard ware conditions. On the other hand, its software structure was divided into 3 modules on basis of functions, which were controlling layer, communication layer and implement layer. Three layers cooperated with each other, and upgraded the whole control system together. Each layer's functions were introduced in detail, and keys to all touchy problems which were discussed in depth were concluded. In order to improve the system's performance, remote crossing debugging methods were put forward and its implemented scheme was given concretely.In the end, the in-circuit upgrading technology on base of field bus had been applied to vehicle body control system, using vehicle field bus network as communication media. The upgrading system via CAN bus was implemented successfully, and the in-circuit upgrading technology was tested by practice.