The Design of Freight Elevator Running System Based on PLC
ABSTRACT
In the wake of utilization in computer technology and the development and improvement of solid power device, elevator controlling technology has become modern technology since the first half of the 20thcentury, which is constant current speed regulation to alternating current varying frequency speed regulation. As introducing international standard and advanced products and technologies from developed countries, freight elevators as a kind of elevators have been developed and improved in our country.
The article introduces the origin and the development of the elevator and the characteristics of the freight elevator with the present situation, and the design of the objectives, contents and significance. At first gives the definition, types, composition, which hopes to have a preliminary understanding of the lift. And then describes the PLC’s stage of development, definition, the basic structure and working principle, performance and features,PLC’s application and selection, describing the basic composition of the inverter, classification, the vector control principle of the inverter and VVVF elevator control features. The design of the freight elevator control system is the system with random logic control. In addition the article also introduces the principle of PLC and hardware design of the VVVF freight elevator and the VVVF freight elevator software program designation.
In this design, three-store freight elevators can be applied by PLC controlling and activated with variable frequency. Also, the computer communication succeeds to operate on the surveillance of the freight elevator and completes the running controlled indirectly on the computer. Therefore, it is supposed that it is feasible to use PLC to control freight elevators and focus on monitoring them between buildings.
Key Words: programmable controller, freight elevator controlling, frequency transformer,PLC , monitoring function