With the rapid development of network technology and smart phones, the technology for remotely monitoring and monitoring the operation of the control unit PLC of the equipment system through the mobile APP is very mature. The PLC remote monitoring and control system based on the mobile APP can bring high economic benefits to both the manufacturer and the user of the device. The user of the equipment can observe the running status of the equipment at any time and timely provide early warning, which improves the reliability of the equipment operation and avoids unnecessary losses caused by equipment failure. Production can also remotely check the operating status of the equipment in real time to eliminate faults, improve the timeliness of after-sales maintenance, improve customer satisfaction with the product, and enhance the brand of the product.
Advantages and features of PLC remote monitoring system based on mobile APP:
1. The remote monitoring system can make full use of the source of intelligence in different places. It can enable remote experts to obtain remote monitoring data through the network, analyze and process them, and realize remote monitoring.
2. The remote monitoring system can make full use of the material resources in different places. Through the use of this technology, sharing and remote experiments of off-site material resources can be realized.
3. The management personnel use the remote monitoring system to monitor the working conditions of the site without having to visit the harsh on-site environment, complete the setting and adjustment of parameters, and repair the faults.
4. The application of remote monitoring system can realize the rapid concentration and real-time collection of field operation data, obtain the monitoring data on site, and provide the material basis of remote fault diagnosis technology.
Second, the principle of mobile APP remote monitoring PLC systemThe mobile APP remote monitoring PLC system is an advanced technology that combines network communication technology and control technology. The development of information technology has enabled the rapid development of remote monitoring technology. Remote monitoring technology is a combination of remote monitoring and remote control. Remote monitoring refers to remotely obtaining data information of monitored resource objects. Remote control refers to remote sending commands to control the running status of field resource objects. A remote monitoring system usually consists of a remote monitoring system, a long-distance data transmission, and a field monitoring system. The basic structure model is shown in Figure 1. The three subsystems work together to achieve remote resource monitoring.
Figure 1: Block diagram of the mobile APP remote monitoring PLC system
Third, the mobile phone APP remote monitoring PLC system hardware componentsAs a high-performance control device, PLC has the advantages of stable and reliable, complete functions, flexible application, convenient operation and maintenance, and is widely used in industrial control systems. However, the PLC generally uses a dedicated communication protocol. The APP uses a network communication protocol to generally communicate directly with the PLC. Therefore, the field control terminal needs to add a remote communication terminal to realize the conversion of the PLC-specific protocol and the APP communication protocol. In this remote monitoring system, we use the PLC-specific remote control terminal of GRM500 series of Guangzhou Jukong to realize the conversion of communication protocol.
Therefore, the system hardware consists of mobile phone, GRM500/GRM200 remote communication module and PLC.
Figure 2: System hardware block diagram
1, plc selection
Siemens S7-200 series, this type of PLC has a large amount of storage in the market, a lot of use, stability and reliability are guaranteed, the price is right.
2. GRM500 remote control terminal
GRM500 remote control terminal is a 4G wireless communication module developed and produced by Guangzhou Jukong. It also supports multiple communication modes such as WiFi, wired network, SMS and voice, and is compatible with 2G/3G network, completely solving the problem of traditional wireless module instability. . Built-in web publishing, a module can realize PLC remote monitoring ladder diagram, download program, LAN monitoring, mobile computer web browsing and so on.
GRM500 and PLC are interconnected through 485, 232 or PLC Ethernet interface, and the module can be connected to the Internet to download, maintain and monitor the PLC remotely. PLCs supported by GRM500 include general-purpose PLCs such as Siemens, Mitsubishi, and Omron. They also support standard MODBUS protocols and various controller protocols at home and abroad.
Fourth, mobile APP remote monitoring PLC system communication method1. Communication between PLC and GRM500/GRM200
Giant Control's GRM500/GRM200 remote control terminal, embedded with a variety of PLC communication protocols, so when communicating with Ximen S7-200, select PPI protocol in GRM500/GRM200 compiler development environment, com1 port or com2 of GRM500/GRM200 The port is 485 port, and the PPI communication protocol settings are shown in Figure 3 to Figure 6:
Figure 3: Select communication port COM1 or COM2
Figure 4: Double-click the communication port COM1 or COM2 to select the PPI protocol.
Figure 5: PPI Protocol Related Settings
Wiring diagram of 485 of Siemens S7-200 and GRM500/GRM200 Figure 6.
Figure 6: Wiring diagram of the 485 port of PLC and GRM500
2. Communication between GRM500 and giant cloud server
GRM500/GRM200 and the cloud server communicate with each other through wired, wifi or mobile phone cards. They use a unique communication protocol between them. No need for fixed IP and any port mapping, peanut shell dynamic domain name multi-package concurrent acquisition, On-demand collection, intelligent compression technology, relatively transparent transmission of GRPS DTU reduces 50% of traffic, speed increased by 2.5 times.
3. Communication between mobile APP and giant cloud server
The cloud server of Jukong has a free standard WEB interface protocol, which can automatically realize the free conversion of WEB protocol and PPI protocol. The developer of APP only needs to know the standard WEB communication, and does not need to know the PPI protocol. This greatly reduces the difficulty of developing the APP. Figure 7 is a screenshot of the directory of the communication protocol specification for the giant control free WEB interface.
Figure 7: Screenshot of the directory of the giant control cloud server WEB interface protocol specification
At the same time, the giant control also provides a universal Android system app for free. The general remote monitoring APP is shown in Figure 8.
Figure 8: Giant Control Free APP Screenshot
Fifth, the actual use of the project
A project requires the APP terminal to monitor the operation information and water level measurement information of the nine units, and wirelessly monitor the unit operation information and water level information through the mobile APP. Below is a partial picture of the project site.
a thing that joins together two parts of sth, two vehicles or two pieces of equipment.
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