| The elevator industry in China has entered a stage of rapid development, bothproduction and sales have been ranked first of the world. The vertical elevator as transporttool has become an indispensable part of the people’s lives. With the rapid development ofcomputer technology, power electronics and automatic controlling techniques, the elevatorindustry has entered a higher level. Variable voltage and variable frequency (VVVF)speed modulation and logic controller composed of programmable logic controller (PLC)have made up the current elevator control technology. In the pursuit of speed, simplicityand comfort of the modern elevators, at the same time, higher requirements in improvingsafety performance and energy efficiency are also put forward.The Siemens S7-200series CPU224PLC has been selected according to theestimation of I/O points. The variable frequency speed modulation technology is used toimprove the elevator’s efficiency and save the energy, and VS-61665inverter is applied tothis subject. In order to obtain smooth speed regulation and good comfort,the velocity curve in the design adopted in starting and braking could be described as twosections of parabola and a straight line. Meanwhile, the acceleration slope and parabola’svatiation rate determine the curve shape and changes. By using a rotary encoder to issuethe pulse signal which is constituted the position feedback, the accurate displacementcontrol of the elevator could be achieved. The elevator control system has a mean layer,the Office of calls to the layer selected, manual and automatic functions with a set offeatures to control the election.In view of the situation of the domestic elevator industry, this paper shows anelevator control system based on PLC. It implements the following functions: switchcontrol of elevator door, registration and elimination of internal and external summoninstruction, display of floors, call bell control, fault alarm, and oriented or reverseinterception etc. |
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