基于PLC的電梯控制系統(tǒng)設(shè)計(jì)與實(shí)踐外文翻譯中英對(duì)照

1、 2021 Workshop on Power Electronics and Intelligent Transportation SystemDesign and Practice of an Elevator Control System Based on PLCXiaoling Yang1, 2, Qunxiong Zhu1, Hong Xu11 College of Information Science &Technology,Beijing University of Chemical Technology, Beijing 100029, China2 Automati

2、on College of Beijing Union University,Beijing,100101, Chinayxl_lmy sina, zhuqx/0>., Abstract This paper describes the development of 2 nine-storey elevators control system for a residential building. The control system adopts PLC as controller, and uses a parallel connection dispatching rule bas

3、ed on "minimum waiting time" to run 2 elevators in parallel mode. The paper gives the basic structure, control principle and realization method of the PLC control system in detail. It also presents the ladder diagram of the key aspects of the system. The system has simple peripheral circui

4、t and the operation result showed that it enhanced the reliability and performance of the elevators.Introduction With the development of architecture technology, the building is taller and taller and elevators become important vertical transportation vehicles in high-rise buildings. They are respons

5、ible to transport passengers, living, working or visiting in the building, comfortable and efficiently to their destinations. So the elevator control system is essential in the smooth and safe operation of each elevator. It tells the elevator in what order to stop at floors, when to open or close th

6、e door and if there is a safety-critical issue The traditional electrical control system of elevators is a relay-controlled system. It has the disadvantages such as complicated circuits, high fault ratio and poor dependability; and greatly affects the elevators running quality. Therefore, entrusted

7、by an enterprise, we have improved electrical control system of a relay-controlledelevator in a residential building by using PLC. The result showed that the reformed system is reliable in operation and easy for maintenance This paper introduces the basic structure, control principle and realization

8、 method of the elevator PLC control system in detail.System structure The purpose of the elevator control system is to manage movement of an elevator in response to users requests. It is mainly composed of 2 parts:2.1 Electric power driving system The electric power driving system includes: the elev

9、ator car, the traction motor, door motor, brake mechanism and relevant switch circuits. Here we adopted a new type of LC series AC contactors to replace the old ones, and used PLCs contacts to substitute the plenty of intermediate relays. The circuits of traction motor are reserved. Thus the origina

10、l control cabinets disadvantages, such as big volume and high noise are overcome efficiently.2.2 Signal control system The elevators control signals are mostly realized by PLC. The input signals are: operation modes, operation control signals, car-calls, hall-calls, safety/protect signals, door open

11、/close signal and leveling signal, etc. All control functions of the elevator system are realized by PLC program, such as registration, display and elimination of hall-calls or car-calls, position judgment of elevator car, choose layer and direction selection of the elevator, etc. The PLC signal con

12、trol system diagram of elevator is showed in Figure 1. Figure 1 PLC signal control system diagram2.3 Requirements The goal of the development of the control system is to control 2 elevators in a 9-storey residential building. For each elevator, there is a sensor located at every floor. We can use th

13、ese sensors to locate the current position of the elevator car. The elevator car door can be opened and closed by a door motor. There are 2 sensors on the door that can inform the control system about the doors position. There is another sensor on the door can detect objects when the door is closing

14、. The elevator cars up or down movement is controlled by a traction motor. Every floor, except the first and the top floor, has a pair of direction lamps indicating that the elevator is moving up or down. Every floor, has a seven segment LED to display the current location of the elevator car. The f

15、irst step for the development of the elevator control is to define the basic requirements. Informally, the elevators behavior is defined as follows. 1Running with a single elevator Generally, an elevator has three operation states: normal mode, fire-protection mode and maintenance mode. The maintena

16、nce mode has the highest priority. Only the maintenance mode is canceled can the other operation modes be implemented. The next is fire-protection mode, the elevator must return to the bottom floor or base station immediately when the fire switch acts. The elevator should turn to normal operation mo

17、de when the fire switch is reset. Under normal operation mode, the control systems basic task is to command each elevator to move up or down, to stop or start and to open and close the door. But is has some constraints as follows: Each elevator has a set of 9 buttons on the car control panel, one fo

18、r each floor. These buttons illuminate when they are pressed and cause the elevator to visit the corresponding floor. The illumination is canceled when the corresponding floor is visited by the elevator. Each floor, except the first and the top floor, has two buttons on the floor control panel, one

19、to request an upelevator, one to request a down-elevator. These buttons illuminate when they are pressed. The illumination is canceled when an elevator visits the floor, then moves in the desired direction. The buttons on the car control panel or the floor control panel are used to control the eleva

20、tors motion. The elevator cannot pass a floor if a passenger wants to get off there The elevator cannot stop at a floor unless someone wants to get off there. The elevator cannot change direction until it has served all onboard passengers traveling in the current direction, and a hall call cannot be

21、 served by a car going in the reverse direction. If an elevator has no requests, it remains at its current floor with its doors closed. 2Parallel running with two elevators In this situation, there are two elevators to serve the building simultaneously. It runs at 7am to 9am and 5pm to 7pm every day

22、. When an elevator reaches a level, it will test if the stop is required or not. It will stop at this level when the stop is required. At the same time, to balance the number of stops, the operation of two elevators will follow a certain dispatching principle. An elevator doesnt stop at a floor if a

23、nother car is already stopping, or has been stopped there. The normal operation of elevators is implemented by cooperation of its electric power driving system and logic control system.3. Software design Due to the random nature of call time, call locations and the destination of passengers, the ele

24、vator control system is a typical real-time, random logic control system. Here we adopted collective selective control method with siemens PLC S7-200 CPU226 and its extension modules. There are 46 input points and 46 output points in the system. The I/O points are showed in Table1. Table 1 I/O addre

25、ss distributeInput pointsOutput pointsdescriptionaddressdescriptionaddress About software designing, we adopt the modularized method to write ladder diagram programs. The information transmission between modules is achieved by intermediate register bit of PLC. The whole program is mainly composed of

26、 10 modules: hall-call registration and display module, car-call registration and display module, the signal combination module, the hall-call cancel module, the elevator-location display module, the floor selection module, the moving direction control module, the door open/close module, the mainten

27、ance operation module and the dispatching module under parallel running mode. The design of the typical modules is described as follows:3.1 Hall-call registration and display There are two kinds of calls in an elevator: hall-call and car-call. When someone presses a button on the floor control panel

28、, the signal will be registered and the corresponding lamp will illuminate. This is called hall-call registration. When a passenger presses a button in the elevator car, the signal will be registered and with the corresponding lamp illuminated. This is called car-call registration. Figure2 shows the

29、 ladder diagram of up hall-calls registration and display. The self-lock principle is used to guarantee the calls continuous display. Figure 2 up hall-call registration and display3.2 The collective selection of the calls Here the collective selection control rules are used. As showed in Figure3, M5

30、.1-M5.7, M6.0 and M6.1 are auxiliary relays in PLC. They denote the stopping request signal of 1st to 9th floor respectively. The auxiliary relay M6.2 denotes the elevator drivers operation signal. When there is a call in a certain floor, the stopping signal of corresponding floor will output. When

31、the elevator is operated by the driver, the hall-calls will not be served. And the elevator cannot pass a floor at which a passenger wishes to alight.3.3 The cancellation of the calls The program of this module can make the elevator response the hall-calls which have the same direction as the cars c

32、urrent direction, and when a hall-call is served, its registration will be canceled. The ladder diagram of up hall-calls cancellation is showed in Figure4. Figure 3 The combination of the calls Figure 4 The cancellation of up calls In Figure4, the auxiliary relay M4.0 is the up moving flag of the el

33、evator. When the current direction of the elevator is up, M4.0s contacts are closed; on the contrary, when the current direction of the elevator is down, M4.0s contacts are opened. M0.1 to M0.7 denotes the car-calls stopping request signal of floor 2 to floor 8 respectively. This program has two fun

34、ctions: 1 Make the elevator response the normal down hall-calls when it is moving down, and when a down hall-call is served, its registration is canceled. 2 When the elevator is moving up, the corresponding floors down hall-call it passing by is not served and the registration is remained. The cance

35、llation of down hall-calls is reversed with up hall-calls.3.4 Elevators direction The elevator may be moving up or down, depending on the combination of hall-calls and car-calls. The following ladder diagram in Fig.5 illustrates that the elevator will move up. Figure 5 Up moving of the elevator Figu

36、re5 shows that when the calls corresponding floor is higher than the elevators current location, the elevator will go up. Here the auxiliary relay M4.0 is used as the up-moving flag. When the elevator is moving up, the up-moving lamp is illuminated, so the M4.0 is connected on. When the elevator arr

37、ives the top floor, the up-moving lamp is off and the timer starts. After 0.2s, the M4.0 is disconnected, the up-moving display is off. Here we used M4.0 to replace Q3.1 which can ensure the cancellations reliability.3.5 Elevators floor-stopping Figure6 shows the ladder diagram of the elevators floo

38、r-stopping function. As showed in Figure6, M6.4 is the flag of floor-stopping signal. M6.6 is the floor-stopping signal sent by the driver. M7.0 is the fire signal sent by the fire switch. And M6.7 is the forced speed changing signal. When either of these contacts act, the system should send out the

39、 floor-stopping signal. Figure 6 The elevators floor-stopping4. Minimum waiting time algorithm In traffic of elevator systems, there are two types of control task usually. The one is the basic control function to command each elevator to move up or down, to stop or start and to open and close the do

40、or. The other is the control of a group of elevators. The main requirements of a group control system in serving both, car and hall calls, should be: to provide even service to every floor in a building; to minimize the time spent by passengers waiting for service; to minimize the time spent by pass

41、engers to move from one floor to another; to serve as many passengers as possible in a given time1. There are many dispatching algorithms for elevators group control. Such as Nearest-neighbor Algorithm2, which the elevator always serve the closet request next; Zoning Algorithm3 which by analyzing th

42、e traffic of elevator system with unequal floor and population demand to dispatch the elevator; and Odd-even rule, which an elevator only serves the odd floor and the other only serves the even floor The Nearest-neighbor Algorithm minimizes the length of the elevators empty move to the next request.

43、 It usually has very small average waiting times, but individual waiting times can become quite large2. The Zoning Algorithm usually used in buildings which has heavy traffic situations, such as the office building at lunch time. Compared to the office building and shopping mall, the traffic flow of

44、 residential buil dings is relatively low and even in every floor. Secondly, people usually think of elevators as purely functional objects and the experience of riding an elevator is time waited for most of them. Furthermore, there exist immense problems when attempting to satisfy all requirements.

45、 Considering all of the reasons above, we adopted the “minimum waiting time algorithm to realize the 2 elevators parallel running4.4.1 Evaluation function The goal of the “minimum waiting time algorithm is to predict the each elevators response time according to all calls, and select the elevator wh

46、ich has the shortest response time to serve. When there is a call, the system calculates out the function values of each elevator according the evaluation function showed in 1 and 2: J*MinJ1,J2,Jn1 JiTri+KTdi+KToi i1,2,n 2 Ji is the evaluation index of each elevator; Tri denotes the time of the elev

47、ator directly moving to the destination corresponding the latest call from its current floor; Toi denotes the additional acceleration and deceleration time of a floor-stop of the elevator; Tdi denotes the average time of the passenger boarding and alighting the elevator; and K is the sum of hall-cal

48、ls and car-calls. But when a hall-call and a car call corresponds the same floor, the K is only calculated one time.4.2 Calculation of minimum waiting time In equation 2, K is a certain value, To and Td can be obtained by means of statistics. Tr T*L, where T denotes the average time of the elevator

49、passing by one floor; L denotes the desired floors of the elevator from current floor to the hall-call floor. In order to calculate the L value, we defined the 2 elevators are A and B respectively; YA,YB denotes the current floor of elevator A and B respectively. H is the corresponding key value when a hall-call button is pressed, and Hfloor number of the hall-call. We defined 4 tables for the PLC realization: up hall-call registration table, down hall-call registration table, car-call registration table of A and car-call registration table of B When a certain call button is pressed, its f