Human beings use transport tools to transport goods, personnel history is very long. As early as 2600 BC the Egyptians in the construction of the pyramid on the use of the original lift system, the basic principles of this system is still no change: A counterweight to decline at the same time, rising load platform. Life continues, technology is developing, and elevators are also improving. 150 years, lift material from the black and white color, style of the straight road type, the manipulation of control is a new step by step - the handle switch, button control, signal control, set selection control, man-machine conversation and so on, elevator also appeared in parallel control, intelligent control. Today, in any city in our country, elevators are widely used. Elevator brings convenience to people's lives, but also provides a strong guarantee for the accelerated development of China's modernization. The elevator control system is divided into relay control system elevator and PLC control system. The most commonly used in life is the PLC control system elevator. This article is through the PLC (programmable controller) designed to control the elevator, in order to achieve easy to use. This design works from a brief introduction to the elevator, and then introduced in detail based on the Siemens S7-200 series PLC to achieve the teaching floor of the Mingde floor elevator control system.
1.1. Research Background and Significance of the Subject
Elevator is a high-rise hotel, shops, residential, multi-story factory buildings and warehouses and other high-rise buildings indispensable vertical transport. With the development of society, the scale of the building is more and more large, and the floor is more and more, which brings forward higher requirements for the static and dynamic characteristics of the elevator speed control precision, speed range. Elevator is a complex system of mechanical and electrical integration, not only involves mechanical, electrical and civil engineering fields, such as, should also consider issues such as reliability, comfort and aesthetics. And for modern elevators, should have a high degree of security. In fact, a number of safety measures have been adopted on the elevator. In the design of the elevator, the mechanical parts and electrical components have taken a lot of safety factor and insurance factor. However, only the elevator manufacturing, installation commissioning, after-sales service and maintenance are to achieve high quality, so as to fully guarantee the final high-quality elevator. In foreign countries, had “regulations” to implement elevator manufacturing, installation and maintenance of integration, It provides the professional installation team maintenance units approved by the manufacturing enterprises, and undertakes the installation and commissioning, regular maintenance and inspection tests, thus providing the guarantee for the reliability and safety of the elevator operation. Therefore, it can be said to take the elevator more secure. An insurance company in the United States has done a serious investigation and scientific calculation of the safety of the elevator. The conclusion is that the elevator is five times safer than the stairs. According to statistics, the number of other means of transport in the United States is about 8 billion people a year, while the number of people taking the elevator every year there are as many as 54 million people.
At present, the programmable logic controller (PLC), which is composed of microcomputer, is developing rapidly. The elevator with PLC control has high reliability, easy maintenance and short development period. This elevator is more reliable and has great flexibility. It can complete more complicated control tasks and has become the development direction of elevator control. Programmable controller PLC in the modern industrial automation control is the most worthy of attention to advanced control technology. PLC has become one of the three pillars of modern industrial control (PLC, CAD / CAM, ROBOT), and is widely used in machinery, chemical industry, petroleum, metallurgy, light industry, electronics, textile, food and transportation industry.