可编程序控制器(PLC)因其结构简单、可靠性高、维护方便等优点，可用于电梯控制。利用PLC S7-200 PLC控制电梯的四层，对四层电梯的PLC控制系统设计直观的描述。详细介绍了PLC控制的四层电梯的设计要求，并列出了输入输出点。
所谓电梯控制技术是指电梯的传动系统及操纵系统的电气自动控制。作为我国 2 0 世纪 70 年代电梯的主要标志是交流双速电梯。其调速方法是采用改变电梯牵引电动机的极对数，两种或两种不同级对数的绕组，其中极数少的绕组称为高速绕组，极数多的绕组称为低速绕组。高速绕组用于电梯的起动及稳速运行，低速绕组用于制动及电梯的维修。
80 年代初，VVVF变频变压系统控制的电梯问世。它采用交流电动机驱动，却可以达到直流电动机的水平，目前控制速度已达 6 米/秒。它的体积小，重量轻，效率高，节省能源等几乎包括了以往电梯的所有优点。是目前最新的电梯拖动系统。
随着城市建设的不断发展，高层建筑不断增多，电梯在国民经济和生活中有着广泛的应用。电梯作为高层建筑中垂直运行的交通工具已与人们的日常生活密不可分。实际上电梯是根据外部呼叫信号以及自身控制规律等运行的，而呼叫是随机的，电梯实际上是一个人机交互式的控制系统，单纯用顺序控制或逻辑控制 是不能满足控制要求的，因此，电梯控制系统采用随机逻辑方式控制。目前电梯 的控制普遍采用了两种方式，一是采用微机作为信号控制单元，完成电梯信号的采集、运行状态和功能的设定，实现电梯的自动调度和集选运行功能，拖动控制则由变频器来完成; 第二种控制方式用可编程控制器(PLC)取代微机实现信号集选控制。从控制方式和性能上来说，这两种方法并没有太大的区别。国内厂家大多选择第二种方式，其原因在于生产规模较小，自己设计和制造微机控制装置成本较高;而PLC可靠性高，程序设计方便灵活，抗干扰能力强、运行稳定可靠等特点，所以现在的电梯控制系统广泛采用可编程控制器来实现。
Peng D. The Application of PLC in Elevator Control System[J]. Journal of Nanchang Institute of Aeronautical Technology, 2000.
With the development of China's economy, PLC applications are constantly popular, while driving the traditional control of the update, its application is extremely extensive. The elevator as a modern high-rise building a means of transport, and people's lives are inseparable, with the improvement of people's living standards, the elevator running safety, efficiency, comfort and other requirements also rose, making the elevator got Rapid development, the current way of controlling the elevator commonly used in two ways, one is composed of traditional relay control system; the second control method is to replace the PLC with programmable logic controller control system. The purpose of this design is to compare the advantages and disadvantages of the control system composed of the traditional relay and the control system of the PLC. The advantages of the PLC are reflected, and the S7-200 PLC is used to control the elevator, and the programming language is used to realize the Elevator automatic operation of the control function, which greatly improve the reliability of the elevator.
Programmable controller (PLC) because of its simple structure, high reliability and easy maintenance, etc., can be very good for elevator control. Through the use of programmable controller S7-200 PLC control four-story elevator work, intuitive description of the four-story elevator PLC control system design method. Details of the four-story elevator through the PLC design requirements, the specific list of the input and output points, and gives the system ladder design.
Key words: Programmable control devices;S7-200;PLC;Four-story elevator
Composed by the order of relay control system is a realization of the first elevator control method. However, to enter the nineties, with the development of science and technology and the widespread application of computer technology, the safety of elevators, reliability of the increasingly high demand on the relay control weaknesses are becoming evident.
Elevator control system relays the failure rate high, greatly reduces the reliability and safety of elevators, and escalators stopped often to take with the staff about the inconvenience and fear. And the event rather than taking the lift or squat at the end of the lift will not only cause damage to mechanical components, but also personal accident may occur.
Programmable Logic Controller (PLC) is the first order logic control in accordance with the needs of developed specifically for industrial environment applications to operate the electronic digital computing device. The PLC biggest characteristics lie in: The electrical engineering teacher already no longer electric hardware up too many calculations of cost, as long as order the importation that the button switch or the importation of the sensors order to link the PLC up can solve problem, pass to output to order the conjunction contact machine or control the start equipments of the big power after the electric appliances, but the exportation equipments direct conjunction of the small power can.
PLC internal containment have the CPU of the CPU, and take to have an I/ O for expand of exterior to connect a people's address and saving machine three big pieces to constitute, CPU core is from an or many is tired to add the machine to constitute, mathematics that they have the logic operation ability, and can read the procedure save the contents of the machine to drive the homologous saving machine and I/ Os to connect after pass the calculation; The I/ O add inner part is tired the input and output system of the machine and exterior link, and deposit the related data into the procedure saving machine or data saving machine; The saving machine can deposit the data that the I/ O input in the saving machine, and in work adjusting to become tired to add the machine and I/ O to connect, saving machine separately saving machine RAM of the procedure saving machine ROM and dates, the ROM can do deposit of the data permanence in the saving machine, but RAM only for the CPU computes the temporary calculation usage of hour of buffer space.
The PLC anti- interference is very and excellent, our root need not concern its service life and the work situation bad, these all problems have already no longer become the topic that we fail, but stay to our is a concern to come to internal resources of make use of the PLC to strengthen the control ability of the equipments for us, make our equipments more gentle.
PLC language is not we imagine of edit collected materials the language or language of Cs to carry on weaving the distance, but the trapezoid diagram that the adoption is original after the electric appliances to control, make the electrical engineering teacher while weaving to write the procedure very easy comprehended the PLC language, and a lot of non- electricity professional also very quickly know and go deep into to the PLC.
Given its advantages, at present, the relay control the lift has been gradually replaced by PLC control. At the same time, AC variable frequency motor speed control technology, the way the lift drag speed has been a gradual transition form DC to AC frequency converter. Thus, PLC control technology increases VVVF Elevator modern technology has become a hot industry.
1. PLC elevator control advantages:
(1) Used in elevator control PLC, with so ware for automatic control of lift operation, reliability greatly increased.
(2) Layer was removed and majority of the relay, the control system structure is simple, simplify the external circuit.
(3) PLC can be a variety of complex control system, easy to add or change control functions.
(4) PLC can be automated fault detection and alarm display to improve the operation of security and ease of maintenance.
(5) For the group control the allocation and management, and improve the efficiency of elevator operation.
(6)Do not need to change the control scheme changes when the hardware connection.
2. VVVF elevator control characteristics.
With the power electronics, microelectronics and computer technology to control the rapid development of technology, communication technology VVVF also a very rapid rate. AC variable frequency motor speed control technology is the power to improve the process in order to improve product quality and improving the environment and promoting technological progress as a primary means. Frequency of its excellent performance and the speed brake from a smooth performance, high efficiency, high power factor and power-saving of a broad scope of application and many other advantages of being at home and abroad recognized as the most promising approach speed.
Exchange characteristics of VVVF Elevator:
(1) low energy consumption.
(2) low load circuit, the re emergency power supply device of small.
In the acceleration stage, the required start-up current of less than 2.5 times the rated current. Peak starting current and time is short. Since the starting current is drastically reduced, so power consumption and power supply cable diameter can be reduced a lot. Required for emergency power supply devices are also relatively small size.
(3) high reliability and long service life.
(4) good comfort.
Elevator operation is best to follow the speed curve of a given operation. Their characteristics can be adapted to human feelings, and to ensure that noise operation, smooth brake Ping layer and high precision.
(5) stable noise-free.
(6) In the car, the engine room and adjacent areas to ensure that noise. Because their systems use a high clock frequency. Always produce a true sine wave power supply current yet. Motor torque ripple does not appear. Therefore, to eliminate vibration and noise.
3. Elevator control technology.
The so-called elevator control technology refers to the elevator drive system and electrical control system of automatic control. 70 as the 20th century in China’s elevator were marked by the exchange of two-speed elevator. Its speed is used to change the elevator traction motor of the very few, two or mute-level approach to the number of windings, very few of them as high-speed winding of the winding, a very few number of windings as the low-speed winding. Windings for high-speed elevator-speed start-up and running, low-speed windings for braking and the maintenance of elevators.
The early 80s, VVVF inverter controlled variable lift system available. It uses AC motor drivers, are able to reach the level of DC motor, control the speed of the current has reached 6 m/sec. Its small size, light weight, high efficiency, energy saving, inc1uding the past almost all the advantages of the lift. Is the latest elevator drive system
Operation in vertical lift, there is also the starting point of the terminus station. For more than three-story elevator buildings, the starting point of the terminal stations and stops between the had not, the starting point for these stations at the first floor of the terminal located at the highest floor. Starting point in the first floor of the station known as base stations, known as the starting point at both ends of the terminal stations and stations at both ends of intermediate stops between stations.
Outside the station has a call box, box set are used by staff for elevator call button or touch the call button, the general ends of the lift stations in the call box on the Settings button or touch of a button. 1iddle layer of the station set up the call box button or touch button 2. No drivers for the control of elevators, at various stations are set up calls me on a button or touch button. Elevator car and the internal settings (except for debris elevator) to manipulate me. Control box switch on the handle or set up stations and the corresponding layer of buttons or touch-button control box on the touch-control button or command button or touch the city button. Outside the command button or touch-button issue as the signal outside the command signal, within the command button or touch-button issue within the signal as a command signal. 80 In the mid-20th century, the touch button has been replaced by micro-button.
As the elevator call box outside the base station, in addition to set up a call button or touch button, but a1so set a key switch in order to work the elevator clearance. Drivers or management staff to open the elevator to the base station can wriggle through a dedicated key to the key switch. Close the elevator in place to autocratically cut off the elevator control power supply or power supply.
4. PLC Control Elevator Design.
With the continuous development of urban construction, the increasing high-rise buildings, elevators and life in the national economy has a broad application. Elevator high-rise buildings as a means of transport in the vertical run of daily life have been inextricably linked with people. In fact the lift is based on external call control signals, as well as the laws of their own, such as running, and the cal1 is random, the lift is actually a man-machine interactive control system, simple to use control or logic control order can not meet the control requirement, and therefore, elevator control system uses a random control logic. Elevator control is current1y generally used in two ways, first, the use of computer as a signal control unit, the completion of the lift signal acquisition, operation and function of the se, to achieve the lift and set the autocratic scheduling function to run the election, drag the control from inverter to complete; the second control mode with programmable logic controller (PLC) to replace the computer control signal sets the election. From the control and performance, these two types of methods and there is no significant difference. Most of the domestic manufacturers to choose the second approach, because the smaller scale of production there design and manufacture of high cost of computer control devices; and PLC high reliabi1ity, convenient and flexible program design, anti-interference ability, stable and reliable operation of the characteristics of Therefore, the elevator control system is now widely used to realize programmable control.
5. Lift control system.
Lift control system is used to manipulate each control process by managing such commands as running direction, car call, landing call, load signal, landing indication, safety protection.
Lifts in different applications have different load, speed and drive / control modes. Lifts in same application may also have different control mode. Whatever control mode is adopted, the objective is the same, to be specific, according to car call and landing call, lift control system will execute automatic logic judgment to determine which lift will receive signal, which direction lift will run towards and complete programmed control objective through electrical automatic system based on command.
Types of lift control system.
Control system development chronicle indicates that there has appeared many control modes, such as such as relay control, PLC, single computer control, multiple-computer control. Prevailing in different era, these control modes are still employed in lifts now due to massive integrated circuit and computer technology development.
PLC control system.
As abbreviation of programmable logic controller, PLC is an electronic system featuring digital computation. It adopts programmable EPROM to execute logic computation, order control, timing, number counting, arithmetic computation, besides, it can input and output through digital or analogy modes.
The mechanism of PLC control is as follows: input of PLC includes such command signals, as power key to home landing, car call, landing call, various safety switches, position signal, while output of PLC includes contactor, relay, indicators of car / landings and communication unitary, indicators inside car and switch, position signal, are input to PC, while other executing com.
Programming principle is determined by lift control mode. Programming can either be made according to relay logic control circuit or individually in different phases according to lift control functions after completely separating from relay control circuit. Based on the ready made control circuit, the former is simple and easy to master, while the latter involves less programs by integrating programs of small function.
Used in lift control system, PLC has such advantages, as high reliability, stability, easy programming, user-friendliness, convenient maintenance & inspection.
Nowadays, there is a wide range and series of programmable logic controllers. Input / output points range from 30 to 8000 or above, so as to meet lift control requirements with different landing number.