1、 Technical background
At present, China’s economy is developing rapidly, people’s living standards are constantly improving, and the living environment is changing with each passing day. Among them, people have higher and higher requirements for the quality and quantity of domestic water. China is a country with relatively scarce water resources. Especially in the northwest and northeast regions, the contradiction between existing water resources and daily production and domestic water is more prominent. In this context, the rational development and effective use of water resources, especially tap water, has become a very important topic. In this subject, we should first master the raw data of each link of the production and use of tap water. However, due to the constraints of the current water supply mode and existing management methods, it is impossible to accurately obtain the actual operation of water supply equipment, which brings difficulties to the water supply company to further strengthen the external service quality and modern management level. In addition, with the development of industrial automation and computer network technology, frequency converter, as an important means of AC speed regulation, has been more and more widely used in industrial production. In today’s world, energy shortage has become a global problem, and energy conservation is more important. The application of frequency converter replaces the traditional wind deflector and throttle valve for fans, pumps and compressors in industries such as electric power, petroleum, chemical industry, metallurgy and water resources. It can timely control the air volume and flow according to the load, and significantly improve the energy-saving effect. In addition, it can also improve and adapt to the operating environment, smooth acceleration and deceleration, and improve the processing technology.
The system applies the most advanced GPRS wireless network technology to the frequency conversion and speed regulation water supply system, so that the remote monitoring object parameters (such as current, voltage, frequency and other data and alarm signals) can be transmitted to the control center in real time through GPRS wireless mode, so as to realize the remote monitoring of water pumps in many different places at the same time on the computer of the control center, It can timely grasp the operation status of the water pump and provide a reliable basis for the water supply decision-making of the water supply company. The upper computer of the control center transmits information with the gprs modem through wireless communication, and the gprs modem is connected with the frequency converter through the serial port, so as to achieve the function of remote wireless control of the frequency converter. The upper computer operates, monitors and alarms the frequency converter in real time through the monitoring configuration software, which improves the flexibility of control.
The innovation of this design is to use GPRS wireless network technology to remotely control the frequency conversion speed regulation system. It can be applied to urban heating, hydrological monitoring and so on, especially in urban water supply and farmland irrigation. In view of the current situation of urban water supply and the dispersion of pump stations, the water plant center can not timely understand the specific water supply situation of each pump station. Using this design, we can directly understand the water supply situation of each pump station, carry out remote monitoring and control, and set up water supply according to scientific water supply decisions, so as to achieve the rational utilization of water resources and save water, It can save energy and manpower at the same time. At present, there is a serious shortage of water resources in China. If this technology is applied to farmland irrigation, the utilization rate of water resources can be greatly improved.
2、 System design
2.1 system composition
The system is composed of water pump, frequency converter, GPRS wireless modem and PC with monitoring configuration software, as shown in the figure
2.2 monitoring configuration software
The software adopts force control pcauto3.6 monitoring configuration software. The software provides a solution to directly monitor the industrial site through the Internet / Intranet browser. The data transmission adopts the event driven mode, so it has better real-time performance when accessing the monitoring screen remotely on the Internet; It supports communication with control equipment and force control network nodes in GPRS, CDMA and other mobile modes. GSM SMS alarm management system is convenient to manage alarm information. These features can well communicate with wm-100dtu to complete the control task. The operation steps are as follows:
① Create real-time database db
② I / O drive of 3D force control PCAuto
New I / O device
Set the parameters of the equipment
Communication port and setting
③ Variable definition
④ Animation connection
2.3 GPRS wireless modem
GPRS (General Packet Radio Service) is the abbreviation of general packet radio service. GPRS adopts packet switching technology to efficiently transmit high-speed or low-speed data and signaling. The theoretical maximum rate can reach 171.2kbit/s, and the actual rate depends on GPRS network. GPRS has the characteristics of always on-line, billing by traffic, high communication rate, convenient networking, wide coverage and so on.
This design adopts the industrial version of Shida wm-100 DTU series industrial GPRS wireless modem, which integrates a high-speed embedded processing system and provides TCP / IP protocol stack. Use its serial communication port to connect with the frequency converter, input parameters to the frequency converter, extract parameters from the frequency converter, and master the operation status of the system.
The principle block diagram of wm-100 DTU industry edition is as follows:
The main menu interface of wm-100 DTU configuration is as follows:
C configurations DTU parameter settings
T self test
F set work mode
L list setting displays all parameter configurations
V version info
R reset restart the system
Responsible editor: GT