Design And Realization On Distributed Elevator Control System Based On CAN Field-bus

Field-bus is a kind of serial data communication link, or a kind of communication network of connecting intelligent field-bus equipments with automation system. Its features are that the signal transfer is whole digital, the control function is completely distributed, and it is an open system with unified standard. The CAN(controlled area network) bus, one of the standard field-buses, has high reliability, cheapness, and many merits. This paper introduces a distributed control system of elevator based on CAN bus, and deeply discusses the system structure, design philosophy and implementation method. A distributed control structure and method of embedded system are adopted in this elevator control system. This system not only has characteristics such as strong function, high reliability of PLC, but also has extremely high flexibility and considerably economic profit. The research achievements and innovations in this paper are as follows:According to the characteristics of the elevator control system, a kindof new-type, high-efficient structure----DSP+CPLD structure is put forward.Most important feature of the structure is the flexibility and general usage. In this system, we adopted DSP as the systematic operation unit, CPLD is responsible for I/O. The design is compact in structure and simple in operation.In the design of software, we put forward embedded and systematic design philosophy into elevator control system, and use the priority-based preemptive and round-robin task scheduler to control the elevator.Utilizing the field-bus technology and technology of distributed control system, this paper developed a distributed elevator control system based on CAN bus.