The Beginning of PLC System in Passenger Elevator
Since the first motor-powered elevator in the world was introduced in 1889, the elevator has undergone the process of drum drive and traction drive in the driving mode and gradually formed two different driving modes: DC motor driving and AC motor driving Drag the way. Nowadays passenger elevator has become an indispensable means for people to move in and out of high-rise buildings. And as a manned vehicle, people have put forward higher levels of static and dynamic performance in terms of running smoothness, high speed, accuracy and high efficiency Request.
Due to the early passenger elevator relay control method has a higher failure rate, poor reliability, wiring complexity, once the receiving is not easy to change and other shortcomings, so the need to develop a safe and efficient control. Programmable Logic Controller (PLC) not only retains the relays control system easy to understand, high control accuracy, reliability, control procedures can be changed with the process, easy and computer interface, easy maintenance and many other high-quality performance. Therefore, PLC in the field of passenger elevator control has been widely and in-depth applications.
With the rapid development of microelectronic technology and computer technology, PLC (programmable logic controller) has been widely used in industrial control field. PLC is an electronic control device based on digital computer technology and designed for industrial applications. It uses programmable memory to store user instructions and to perform a series of logic through digital or analog input / output , Order, timing, counting, computing and other functions identified to control various types of mechatronic equipment and production processes.