Abstract: A fully automated monitoring system for a six-story elevator was designed using the WebAccess web configuration software and the ADAM5510 programmable logic controller (PLC). The ADAM5510 communicates with the industrial computer via TCP/IP Ethernet, while the ADAM5510 and WebAccess communicate using the Modbus protocol for variable connections. Real-time monitoring of the elevator operation demonstrates that this monitoring system exhibits good real-time performance and high stability, meeting the requirements of a monitoring system.
Keywords: WebAccess; ADAM5510; elevator; monitoring system
Design of Elevator Monitoring System Based on
WebAccess and ADAM5510
XUE Jianhai1, ZHAO Lei1, ZHAO Wengang1, LIU Jin2
(1. Heating Power and Gas Co. Of Qingdao Economic & Technical Development
Zone,Qingdao,266555 2.College of Automation Engineering，
Qingdao University, Qingdao, 266071
Abstract: Based on the performance characteristics of elevators, this paper realizes automatic supervision of six layer elevators by use of softlogic programmable controller ADAM5510 and broadwin WebAccess. Modbus protocol is used to carry out the communication between ADAM5510 and WebAccess. The system is confirmed to achieve stability and real-time performance, and the requirement of monitor and control is met.
Key words: ADAM5510;WebAccess;configuration software;elevators
introduction
As the main means of transportation in many high-rise buildings, elevators have brought many conveniences to people's daily work and life [1]. Elevators are electromechanical products that combine mechanical and electrical components. There are three main control methods: relay control, microcomputer control, and PLC control. However, the failure rate of relay control systems is relatively high, and the anti-interference capability of microcomputer control systems is insufficient. PLC control is simple, reliable, easy to maintain, and has strong anti-interference capability, making it the mainstream of elevator control. At the same time, the continuous development of configuration software has made elevator monitoring systems more user-friendly and intuitive, and has become a research hotspot in elevator control. This paper takes the elevator model as the monitoring object and develops a monitoring system for a six-story elevator using Advantech ADAM5510 soft logic programmable controller and WebAccess configuration software.
1. Overall System Design
The monitoring system for the six-story elevator mainly consists of the elevator, a microcomputer (with configuration software installed), an ADAM5510, and a motor. Its main functions include: (1) enabling automatic elevator operation, primarily detecting external and internal call signals and controlling the elevator's upward and downward movement; (2) establishing communication between WebAccess and ADAM5510; and (3) monitoring and controlling the elevator's operating status using WebAccess software. The overall block diagram of the control system is shown in Figure 1.
The system's low-level control is achieved through a programmable logic controller (PLC) ADAM5510, a frequency converter, an AC motor, and a speed reduction device. A microcomputer acts as the host computer, monitoring the elevator's operating status. The elevator's operation is controlled by the programmable motor rotation controlled by the ADAM5510, while the host computer uses WebAccess configuration software to monitor the elevator's operating status, enabling real-time monitoring and alarm functions.
Figure 1 System Overall Design Block Diagram
2 Design of ADAM5510 Control System
2.1 Estimation of I/O points
In order to select appropriate analog input/output modules and facilitate system configuration, the number of I/O points of the entire elevator control system should be analyzed first [2].
(1) Lobby call buttons: Located next to the elevator lobby door, except for the top floor (6th floor) which only has a down call button and the bottom floor (1st floor) which only has an up call button, each other floor has two call buttons, one up and one down, for a total of 10 buttons, i.e. 10 input points. When each button is pressed, the indicator light inside the button will automatically light up.
(2) Call buttons inside the elevator car: Located inside the elevator car, these are internal selection signals. There are 6 buttons for every 6 floors, i.e., 6 input points. When each button is pressed, the indicator light inside the button will automatically light up.
(3) Input and output of leveling detection signal: A leveling signal detection device is installed on each floor. When the elevator arrives at or is located on that floor, it is detected by the detection device. There are a total of 6 input points for detection signals on 6 floors. Correspondingly, there are 6 output lights on the outside to indicate the floor where the elevator is located.
(4) Operation status display output: There is one external output point corresponding to the elevator going up, going down and the current floor.
Based on the above analysis, we know that this system has 22 digital input points and 9 digital output points. Therefore, we selected 2 ADAM5051 and 2 ADAM5056 chips. Thus, we installed ADAM5051 analog acquisition modules in slots 0 and 1 of the ADAM5510, and ADAM5056 analog output modules in slots 2 and 3.
2.2 ADAM5510 Communication Settings with Computer
To enable communication between ADAM5510 and other hardware, ADAM5510 provides two serial communication ports: COM1 is in RS232 mode and COM2 is in RS485 mode [3]. In addition, ADAM5510 itself has an Ethernet port, which is convenient for connecting with other hardware via TCP/IP protocol [4]. This system adopts this communication method. In the resource settings properties of the Multiprog software project tree, make the corresponding communication port settings, select the DLL port, and set the IP address of ADAM5510 to be in the same network segment as the computer itself. The two can then communicate through the Ethernet port.
2.3 ADAM5510 Software Programming Implementation
The lower-level programming software Multiprog conforms to the IEC61131-3 standard and supports five standard programming languages, including LD and FBD [3]. This programming software has a graphical programming interface, and different languages can be used in a single project program. It also supports floating-point operations, complex algorithms, simulation testing and online monitoring, serial port download and network download. The system adopts the ladder diagram design method. The program flow is shown in Figure 2.
3. Design of WebAccess monitoring screen
Advantech WebAccess is a fully Internet Explorer-based automated human-machine interface (HMI), monitoring and data acquisition (SCADA) network configuration software. All engineering projects, database maintenance, graphic creation, and software management can be completed remotely using a browser via the Internet.
3.1 Communication Settings
The interface between the configuration software and the ADAM module includes two methods: OPC Server and Modbus protocol. This system uses the Modbus communication protocol and leverages the Modbus/TCP Server function to dynamically link variables in ADAM5510 with variables in WebAccess based on the mapping between Modbus addresses and I/O port addresses. For example, the I/O address of variable 2DownFloor_Modbus is %MW3.0.0, and according to the Modbus address mapping, its address in WebAccess should be set to 02001. Some of the variables created in WebAccess are shown in Figure 4.
3.2 Interface Design
The entire monitoring system mainly includes main control, alarm summary, record query, and system help screens. The real-time monitoring interface (as shown in Figure 4) should primarily include a six-story elevator model diagram, indicator lights for elevator arrival at each floor, external call signals for each of the six floors, internal selection signals within the elevator car, stair up/down output indicator lights, and external digital display floor indicator lights for each floor. The required functionality is as follows: during operation, when the elevator is moving up, down, or arriving at a specific floor, the external indicator lights and digital display will monitor the elevator's operation. When operators want to change the elevator's operation, they can directly use the left mouse button on the monitoring interface of the host computer to operate the external call and internal selection buttons, causing the elevator to automatically move to the designated floor.
Figure 2 Program Flowchart
Figure 3 WebAccess external variables
4. System Testing and Result Analysis
In the actual design process, after the control program was edited on the host computer, it was downloaded to the ADAM5510. First, the elevator was manually debugged to ensure proper operation, and then the WebAccess elevator system monitoring interface was used for testing. For direct monitoring of the actual system, the key is that the external variables required by each display device and button in WebAccess must correspond to the internal Modbus addresses of the ADAM5510. Figure 4 shows the monitoring interface after debugging. The various display devices can effectively track the actual operation of the elevator, and the buttons can control the elevator's operation, achieving the design goals.
5. Conclusion
This paper designs a control system for monitoring the operation of a six-story elevator using Advantech WebAccess configuration software. Modbus technology was employed during the design process to solve the communication problem between the ADAM5510 and WebAccess. Practical application has proven that this WebAccess system can effectively monitor elevator operation and control it via a human-machine interface, with satisfactory monitoring results. This method is simple, easy to implement, highly operable, and cost-effective, possessing significant practical value.
Figure 4 Main monitoring interface
References:
[1] Ai Hui. Application of Siemens S7-200 PLC in elevator serial control [J]. China Elevator. 2002.13(10), 27.
[2] Xu Lei et al. Design of elevator monitoring system based on WinCC and S7-200 PLC [J]. Mechanical Engineering and Automation. 2008, 2: 117-119, 122
[3] Liu Jin, Yu Haisheng, Wu Herong, et al. Design of a dual-tank water level control system based on WebAccess and ADAM5510 [J]. Journal of Qingdao University (Engineering Technology Edition). 2009, 24(2): 6-9
[4] Wang Shudong, Feng Lei, et al. Design of a remote hydrological monitoring system based on ADAM5510 and GSM [J]. Computer Measurement & Control,
2007, 15(1): 24-26.
The communication method is as follows:
Corresponding author: Jin Liu
Contact number: 13791985124
Mailing Address: 2008 Graduate Class, School of Automation Engineering, Qingdao University, No. 308 Ningxia Road, Qingdao, Shandong Province
Postal code: 266071
