Second, GPRS development status and technical analysis: Scope of application of GPRS professional data transmission system The system can be applied to oil field exploration, testing, production, environmental protection water, gas, sound detection, water conservancy and hydrology detection, seismic detection, alarm, power data monitoring, alarm, remote sensing telemetry and other professional data Transmission. Fourth, GPRS data transmission implementation: 2.GPRS wireless data transmission schematic The use of GPRS data transmission network for on-site data monitoring. In the industrial field using a variety of sensors for signal acquisition or analysis of existing data or analog signals, GPRS Modem can be connected to a variety of data acquisition instrumentation through the standard RS232 interface, if you want to connect with RS485 interface equipment, need to pass RS232/RS485 converter (This standard can be easily purchased). In normal working mode, the GPRS transmission module transmits the instrumentation data to the data management server through the mobile communication packet network (GPRS network). The data server can be connected to the internal network of the enterprise through DDN leased line, ADSL, ISDN connection, etc. A central database is set up on the server of the center to sort and store the received data and generate corresponding reports and instructions. And can develop analysis and decision modules on it to determine the working status of the monitoring object (such as whether it is working normally, any abnormal events), and make corresponding instructions on the situation, return to the data terminal to perform, or sent to the management by SMS And maintenance personnel. In this way, real-time monitoring of the operating status of field devices is realized, and data is exchanged among personnel, control centers, and devices, enabling technical personnel and management personnel to obtain data of each monitoring point regardless of their location. Make timely response. 3.GPRS wireless data processing principle 4. Implementation of GPRS wireless data transmission system Automotive Connectors,Automotive Connector,Cable Wire Connectors,Cable Wire Connector YUEQING WEIMAI ELECTRONICS CO.,LTD , https://www.wmconnector.com
Production-oriented large-scale industrial enterprises (such as: metallurgy, chemical industry, petroleum, coal, manufacturing, etc.) have huge scale, many department personnel, scattered operating points, many equipment, high value, a variety of pipelines, valves, a considerable part of the equipment work In the outdoor feature, therefore, it is necessary to monitor the operating status, temperature, pressure, flow rate and other indicators of various equipments. Once the situation occurs, the alarm can be performed in time and can be commanded and adjusted remotely; and general industrial control. The system spans a large area and has a large number of monitoring points. It requires a high speed of the communication system and a faster polling response time. At the same time, some operating points are scattered in the wild and the environment is poor, requiring unattended remote control. Therefore, wireless networks have become an indispensable part of the future development of these industries. At present, there are mainly the following solutions for remote monitoring in China:
1) using satellite communications;
2) Use different high-power (RF) wireless data radio stations;
3) Use telephone dialing;
4) Transmission via mobile public network (GSM/GPRS/CDMA).
Among them, satellite communication, data radio, and telephone dialing are traditional data transmission solutions. These traditional methods have problems such as coverage, real-time, investment, and operating costs. At the same time, there is a large number of unattended operations of industrial control equipment. difficult. At present, the emerging data transmission technologies such as GPRS and CDMA that China Mobile and China Unicom respectively push forward will fundamentally solve the drawbacks of traditional transmission methods and bring them closer to the needs of professional data transmission.
As a data value-added service of China Mobile’s main push, GPRS has undergone nearly a year of technological transformation and upgrading. The system has become stable and reliable. Its coverage has been similar to that of a GSM network, but its rate is relatively low, generally up to 28Kb. CDMA is connected to China. The data service business has the characteristics of high speed, system stability, etc. However, the current coverage is small and it is still unable to provide real large-scale professional data transmission services. From a pragmatic point of view, GPRS as a professional data transmission system network support platform, combined with data encryption technology to ensure the safety of network transmission to achieve a better choice of professional data transmission system.
As a 2.5-generation technology for mobile communications, GPRS is an important step for GSM mobile phone systems to move towards third-generation mobile communications. GPRS is the abbreviation of General Packet Radio Service, which breaks through the GSM network's only way of thinking of providing circuit switching, and realizes packet switching by adding corresponding functional entities and partially modifying existing base station systems. The investment in this kind of transformation is relatively small, but the user data rate obtained is quite considerable. GPRS allows users to send and receive data in the end-to-end packet transfer mode without the need to utilize circuit switched mode network resources. As a result, an efficient and low-cost wireless packet data service is provided. Especially suitable for intermittent, sudden and frequent, small amounts of data transmission, but also for occasional large data transmission. On May 17, 2002 World Telecommunication Day, China Mobile formally launched a commercial trial of GPRS, and its coverage has been close to that of the GSM network.
The advantages of GPRS data transmission:
Always online: Unlike traditional dial-up Internet access, you need to redial after disconnection to surf the Internet. The customer keeps in touch with the network at any time, and even if there is no data transmission, the customer still maintains a connection between the Internet and the network.
Quick login: Connection time is fast. When the GPRS wireless terminal is turned on, it has established a connection with the GPRS network. Each time the user logs in to the Internet, only one activation process is required. Generally, it takes only one to three seconds.
High-speed transmission: As the GPRS network adopts advanced packet switching technology, the highest theoretical value of data transmission can reach 171.2kb/s.
Amount-based charging: The GPRS network collects fees based on the number of packets the customer receives and sends. When there is no data traffic, the customer is not charged even if it is online.
Third, GPRS data transmission system features and application scope
Combining China Mobile's GPRS network and enterprise intranet to set up a GPRS data transmission system, the system has the following features:
Wide coverage: At present, GPRS signals have basically covered all GSM networks, and remote areas no longer become blind areas for data transmission;
Mobility: The enterprise has autonomy over all equipment in the system, and does not need to negotiate with the operator, and can be freely allocated;
Reliable transmission: The system has error correction and retransmission mechanisms to ensure data integrity and correctness;
Data security: The system provides an encryption mechanism during data transmission. Data can be safely transmitted on the public network.
Automatic recovery: The system has the functions of automatic dialing and breakpoint continuous transmission. When the GPRS network is unstable, the system can work stably without human intervention.
Unattended: The system realizes two-way transmission, which can achieve remote control and achieve unattended.
Convenient and versatile: The system can be directly connected with professional data acquisition equipment without secondary development;
Data backup: The system can provide data storage for damage caused by force majeure;
Transparent transmission: The system is designed for the speciality of professional data transmission and is suitable for installation in harsh environment in the field.
Simple and Power Supply: The system has multiple power supply methods. It can use 220V AC direct power supply or 5 ~ 60V DC power supply. It contains high-efficiency DC-DC conversion circuit, strong anti-interference ability, suitable for long-term continuous work.
1. GPRS data transmission mode The GPRS service opened by China Mobile only provides point-to-multipoint transmission services at this stage. GPRS wireless interrupts and point-to-point transmission between GPRS wireless terminals are theoretically feasible, but technically still need better support. Point-to-multipoint transmission refers to multiple GPRS wireless terminals transmitting data to a fixed data processing center. GPRS is based on the transmission of data in the form of IP packets. When a GPRS wireless terminal enters the GPRS network, it is automatically attached to the Internet. Therefore, such transmission does not require GPRS providers to provide more services and support, and it can transmit data from any GPRS coverage area to the center.
At present, China Mobile's GPRS data service is mainly used to provide wireless Internet access for mobile phone users. For the transmission of professional data, integrated developers must use mobile communication networks, Internet networks, and metropolitan area private networks to set up a dedicated data transmission system to develop GPRS. Client software, relay forwarding software, and central processing software; and flexible choice, efficient encryption, and compression algorithm-level licensing agreements to protect professional data and transmission security in open networks.
Note: In the field of industrial monitoring, the use of monitoring methods based on the GPRS network will greatly reduce the operating costs of enterprises, and more easily implement the computer integrated enterprise management (ERPII), so that managers can collect real data in real time and collect data in real time. Field equipment operation status, achieve reasonable management and dispatch, thus saving costs, and creating new profit growth opportunities for it.
ï¬ The data center accesses the Internet and establishes a TCP or UDP connection with the GPRS Modem through Socket communication.
ï¬ GPRS Modem establishes a connection with the base station through the PPP dialing method. It authenticates and obtains an IP address and connects to the Internet.
ï¬ The GPRS Modem obtains the data of the data collection terminal from the serial port and sends it to the data center in the form of UDP or TCP packets. The UDP or TCP packets sent from the data center are converted into serial port data and transmitted to the terminal device.
There are generally two forms of data collection and transmission at the data collection point. One way is to process the collected data through an industrial control computer and integrate it in the form of files or data streams; the other method is without an industrial control computer. The device needs to directly transmit the data stream collected in real time. At the same time, data transmission under both modes may require bi-directional channels. The upstream channel transmits professional data and alarm information, and the downlink channel transmits command data to control start-stop, remote configuration of professional collection equipment.
The GPRS wireless terminal (EP Series Modem) sends data to China Mobile's intranet (CMNET) through the GPRS network, and then China Mobile transmits the data to the Internet through the GPRS Service Node (GSN) and searches for one on the Internet. The designated central server and the central server receive the data through the data receiving software. After the data is received, the data can be forwarded to the designated data processing server of the internal network. The data processing server decrypts the data through data processing software and decompresses the data to restore the original data. At the same time, the reverse transmission of data and instructions can also be realized.
The underlying protocol of the entire transmission system adopts the IP protocol, and a dedicated protocol is loaded at the application layer. The algorithms such as RS, 3DES, and CRC32 are used to control and maintain the security and reliability of links and data, and the data can be guaranteed to be 100% accurate.
GPRS industrial monitoring program
First, background analysis