First partial system overview
GPRS --- General Packet Radio Service, universal wireless packet service is a wireless packet switching technology based on GSM system, providing end-to-end, wide-area wireless IP connections. In a popular, GPRS is a high-speed data processing technology, and the method is to transmit information to the user in the form of "packet". User Internet access can be free of disconnection. Hong Kong has achieved good results in the area of the first GPRS field test. After using GPRS, the data is transmitted and received, and the user can always reducing service costs in line with traffic bills. GPRS service cost is only a very central cost of service costs only CSD (circuit switched data, ie, usually dialing data, and the Eurasian WAP business) service costs. The GPRS Electrical Try The remote meter reading system is a GPRS technology-based electricity management automatic meter reading system based on the development of Xiamen Sangrong Technology Co., Ltd. and System Integration. It consists of an electric meter, a collector and server with a GPRS communication module. The collector collects the user's electricity data in real time, collect the data to the server via GPRS. It has the rapid and accurate collection of data, fast generation of electricity statistical analysis, payment documents, etc., which greatly improves the efficiency compared to traditional artificial meworks and telephone line meter reading. In addition to accurate and real-time meter reading, the system also provides equipment management functions, such as the alarm: unpacking alarm, power outage alarm, reverse alarm, overwesome, overloaded alarm, etc .; control: Turnover the owed users. And provide power outage data protection, still meter reading and monitoring within 48-72 hours. This system combines mobile company's SMS platforms, when alarms, can send text messages to relevant managers according to specific content. This system provides a wealth of interfaces that can be linked to the MIS system of the electric industry or secondary development. Meter reading software system database is an Oracle database, running in WIN98 / 2000 / XP, NT operating system, easy to use. There is no limit to the number of users that the software can manage.
Part 2
This system consists of a primary station with system software, a collector with a GPRS module, an electric meter. The handheld terminal is a supplement to this system and is an accidental meter reading when the system has unexpected. Main station: Computer (server or PC) running a centralized meter reading system is called the primary station, and the master is connected to the collector via the GPRS network. The primary station is to configure a fixed IP address and the Internet export. Collectors with GPRS modules: collecting electric meter data to the data center, which connects the master and electricity meter. Power meter: Measure and display the user's power condition, transfer the electricity information to the GPRS collector. These three main components are inter-associated primary relationships. The entire structure is shown below:
According to the different meter pairs, we design the following three meter reading modes: 2. Resident user meter reading system 1, electric meter: 1.0 single-phase stationary (electronic) electric meter, has a photocoupled impulse output function. 2, collector (GPRS-TY1) with GPRS function: (1) 24 I / O ports, 24-pin table (2) power outage data protection (3) with backup power supply, still copied after power failure Table 3, Meter Reading Content: (1) Electrical amount (2) Other 4, meter reading form: (1) Automatic meter reading (2) Timing report (3) Real-time query 5, alarm content: (1) Open box Alarm (2) Power-off Alert 1, increase remote control tensile function, and the power meter increases the built-in relay. 2. Technical indicators: (1) System capacity: collector capacity: up to 24 pieces of meter; system capacity: In principle, unrestricted, actually determine the capacity of the main station computer; (2) Communication distance: collector With the meter: use two-core multi-strand, for mechanical table, distance ≤ 500m; for electronic meter, distance ≤50m. Main station and collector: using GPRS networks as communication media, distance is unrestricted; (3) Communication success rate: between master station and collector, using TCP / IP protocol based on reliable connection, communication success rate is 100%.
2.2 Large Group User Meter Reading System 1, Meter: A) Three-Phase Grocery Contact Multi-Function Table, Supreme 0.5, Delicate Level 2, has RS-485 Communication Interface, Power Department DL / T645 Communication Statute. Or use: b) three-phase has a functional table, active level 1, with RS-485 communication interface, power division DL / T645 communication protocol. Measurement of metering and power factor, voltage, current, frequency, etc. 2, collector (GPRS-TY2 type) with GPRS function: (1) With a RS-485 interface communication with the electric energy meter, a GPRS interface communication with the master station system, three switching inputs for alarm monitoring Port and three analog output ports for remote control. (2) Support for Bad Tags Communication Standards (3) Power-off Data Protection (4) Control Output (for remote control pull or other functions) (5) Backup backup power supply, still copy table 3 after power failure, system function (1) Set the parameters of the electric energy meter, read various metering and management data; (2) Meter, query, backup, report, chart generation; (3) factory management; (4) Automatic meter reading, regularly, Real-time query, etc .; (5) power-down data storage; (6) comprehensive processing of instantaneous data; (7) system data backup, archive, and outward output data; (8) historical data event recording function; (9) real-time alarm (10) calculate the line loss according to the interface on the line; (11) can provide multiple simulation, switch input, implement unpacking alarm, power outage alarm, reverse alarm, overwesome, overpressive alarm, Other functions such as flow alarms, overload alarms, tilt or mobile alarms; (12) remote control power failure function; (13) Collected parameters rich, such as: ◆ Current, last month, forward, reverse, don't work The total number of quadrants, peaks, flat, valleys; ◆ Positive, reverse, active, reactive achievement and maximum demand time; ◆ active power, reactive power, three-phase voltage, Three-phase current, power factor; ◆ Impressive pressure cumulative number of times, loss of pressure, stable start time, etc.; ◆ Unit time load curve, three-phase current curve, three-phase voltage curve, active power curve, reactive power Curve, power factor curve. 7. Technical indicators: (1) System capacity: Collector capacity: up to 255 pieces of meter; system capacity: In principle, unrestricted each table, actually determine the capacity of the main station computer; (2) Communication Distance: Collector and Meter: Using RS-485 interface and shielded twisted pair, distance ≤500m.
Main station and collector: using GPRS networks as communication media, distance is unrestricted; (3) Communication success rate: between master station and collector, using TCP / IP protocol based on reliable connection, communication success rate is 100%; (4) Fully comply with the IEC1107 standard and national electricity company DL / T645 "multi-function power meter communication statute"; (5) Working power supply: AC 220V ± 20%, 50Hz; (6) Communication rate: 1200bps ~ 33.6kbps; (7) Collector power consumption: ≤1.5W (8) Working environment: temperature: -10 ° C ~ 50 ° C, relative humidity: ≤90%; (9) pressure resistance: 2 kV; insulation resistance: 2m ohm; (10) electric meter Data improver, reliability and read accuracy of 100%. 2.3 Substation meter reading system 1, meter: three-phase active unreasonable multi-function table. 2, collector with GPRS function: (1) with a 485-port, three switches and three analogs; (2) Support for part standard communication stories; (3) power outage data protection; (4) control output; 5) With the backup power supply, you can still mework after the power is powered off.
3, meter reading: (1) voltage, current; (2) active, reverse minute power; reactive four elections limit time; (3) active, reverse minute maximum demand and time; (4) Denual, reverse minute, maximum demand and time; (5) off-phase time, number of times, and electricity during phase phase; (6) load curve. 4, meter reading form: (1) Automatic meter reading; (2) Timed on reporting; (3) real-time query. 5, the alarm content: (1) unpack alarm; (2) power outage warning; (3) reverse the alarm; (4) overwesome warning; (5) overpressive alarm; (6) overload Alarms; (8) other functions such as tilting or moving alarms. 6. Technical indicators: (1) System capacity: collector capacity: up to 255 pieces of meter; system capacity: In principle, it is not limited to each table, and it can actually determine the capacity of the main station computer; (2) Communication Distance: Collector and Meter: Using RS-485 interface and shielded twisted pair, distance ≤500m. Main station and collector: using GPRS networks as communication media, distance is unrestricted; (3) Communication success rate: between master station and collector, using TCP / IP protocol based on reliable connection, communication success rate is 100%.
2.4 System Software GPRS Auto Meter Reading System The core part of the system is system software, which follows the DL / T645 system communication statute and has scalable. Meter reading software system database is an Oracle database, running in WIN98 / 2000 / XP, NT operating system, easy to use. There is no limit to the number of users that the software can manage. The function and characteristics of the system are: (1) Safety and reliability: security is constructed from three aspects: First, the Oracle database is large, multi-user database, which is high security, allowing multiple users to use the same database at the same time without Destroying the integrity, use it to make the data engine of the meter reading system to ensure the security of the data; second, the system implements the user's management function, by checking the user's name and ** password, give the user corresponding operation Right, borrowing the password management mode restriction of the banking system changes the database and hardware settings. Third, firewall function and perfect data backup function, the preparation system is subject to human malicious attack, and the data backup function ensures that the meter reading system can be launched on the new hardware device at any time when the hardware system is faulty. (2) Perfect system log: The system log records the enterprise, leaves the system, charges, set hardware, change the operation parameter operation, etc., and operator, operation time, and all operations that change the database are recorded. (3) Fast meter reading: fast meter reading, accurate data, data transmission of the PC read-only collector, data transmission is 1200 baud rate, the transmission speed is fast, and the code is valid for each data block. Guaranteed the accuracy of the transmission. (4) Broadcast timing function: This function allows the time baseline of all power meter in the system that is consistent with the PC. After the timing is successful, the internal clock is supplied by the battery, and no longer requires an intervention of the PC. Therefore, as long as it is guaranteed that the time is correct, the time of the PC is in the process of running, the clock of the PC does not affect the time of the electric energy meter. (5) Automatic meter reading function: According to the set meter table start time and meter interval, the system will dial the data in the column collector or the meter in turn. For the copy data, the system will automatically copy or manually order. (6) Electrical quantity freeze function: It can be easily defined to define the total table, install and delete the total table, and assign a solution to the headlist. By installing the appropriate total table, combined with the coprorate data function, you can obtain the total table reading of a particular moment, and the readings of each score (thus the reading and) can calculate the power loss of a part of the circuit. Provide a basis for determining electricity bills. (7) Electrical Toll Management Function: Before collecting electricity charge, the electricity fee data is unified. When ensuring that the data in the database reflects the nearest meter reading, the functionality and electricity charges are automatically calculated using the functions in the program. When paying electricity, simply enter the user number, the monthly electricity and electricity bill are filled in. Each electricity fee has a detailed record, which is easy to check. (8) Equipment management function, such as alarm: unpacking alarm, power outage alarm, reverse alarm, overwesome warning, overload alarm, tilt or mobile alarm, etc .; control: Turnover the owed user. And provide power outage data protection, still meter reading and monitoring within 48-72 hours. This system combines mobile company's SMS platforms, when alarms, can send text messages to relevant managers according to specific content. This system has a wide range of adaptation, single-phase version of software can be used in cell management, and the network version of software can be used to power supply companies to implement electricity management in a city or region. The following is the main functional module of the system software: the third part system security
In terms of system security, in addition to using large, multi-user Oracle databases, the system implements the user's management and providing firewall function and the firewall function and a complete data backup function, the GPRS Network Wireless Data Monitoring Center also provides security technology solutions. Solution to ensure that data is safe and reliable. 3.1 Profile of GPRS Agreement GPRS Network Structure GPRS network is to add the following functional entities on the GSM network: Services GPRS Support Node (SGSN), Gateway GPRS Support Node (GGSN) and Point-to-Multi-Point Service Center (PTMSC). The system shared the GSM base station, but the base station should be software update, and use a new GPRS mobile station; GPRS to add new mobility management programs; GPRS backbone network is implemented; GSM network systems should be software update and add new MAP Signaling and GPRS signaling, etc. The main role of the SGSN is to record the current location information of the mobile station, and complete the transmission and reception of the mobile packet data between the mobile station and the GGSN. GGSN is mainly a gateway role, which can be connected to a variety of different data networks such as ISDN, PSPDN, and LAN. GGSN can protocol the GPRS packet packets in the GSM network, allowing these packet data packets to the remote TCP / IP or X.25 network. The logical structure of the GPRS backbone network is shown in Figure 1. Figure 1. Logical structure of the GPRS backbone network The GPRS hierarchical protocol model between the GPRS protocol model mobile station (MS) and SGSN is shown in Figure 2. The UM interface is the air interface of GSM. The communication protocol on the UM interface has 5 floors, which are subject to the physical layer, the MAC (Medium Access Control) layer, the LLC (SUB-NetWork Dependant Convertant) layer and the network layer.
Figure 2. The physical layer of the GPRS network is a radio frequency interface portion, and the physical link layer is responsible for providing a variety of logical channels for air interfaces. Mac is a media access control layer. The main role of Mac is to define and distribute GPRS logical channels for air interfaces such that these channels can be shared by different mobile stations. The LLC layer is a logical link control layer. It is a wireless link protocol based on high-speed data link procedures HDLC. The LLC layer is responsible for forming an LLC address, a frame field on a SNDC data unit of a high-level SNDC layer, thereby generating a complete LLC frame. The LLR layer in BSS is a logical link transfer layer. This layer is responsible for transferring the LLC frame between MS and SGSN. SNDC is called subnet depending on the joint layer. Its main role is to complete the packets, packages, and determine TCP / IP addresses and encryption methods. The network layer protocol is currently mainly TCP / IP and L25 protocols available in the Phase 2 phase. TCP / IP and X.25 protocols are transparent to traditional GSM network devices such as BSS and NSS.
3.2 GPRS and Internet Connections From the GPRS structure, the connection between the base station and the SGSN device is generally connected by the IP network through the frame relay connection, and the SGSN is connected to the GGSN device. The SGSN can assume the conversion of the internal IP address and the external network IP address by the router with the NAT (Network Address Translation) function. MS can access the network within GPRS, or access the external PDN / Internet through the APN (external network access point name). The internet. The following figure simply represents a network structure when a mobile host accesses Internet: The communication between the mobile host and the GPRS network occurs in the LLC layer, the communication control protocol between the mobile host and the content server uses TCP.
Figure 3. Simulation network structure Schematic diagram 3.3 Wireless data transmission system based on GPRS
Figure 4 GPRS system network topology diagram As shown in Figure 4, the "central server" in the figure is the data monitoring center of the system, outside the GPRS subnet, in the Internet network, has a public network IP, its function is quite In the ordinary network server, there is two major characteristics compared to the general business server, first, it is a server serving the GPRS subnet user. Second, its service customer object is pre-knowledge. Combining these two most significant features, the following two security technology solutions are provided. 3.3.1 IP Filtering Technology Due to the monitoring center to serve the GPRS subnet user, all IPs that access customers will be IPs in the GPRS subnet, that is, all users must access the server through CMNET. Therefore, we use IP filtration technology in the system to filter all accepted packets, and abandon all illegal IP datagrams. This process seems to put the system under the firewall protection of the CMNET, all illegal users can only pass the security protection of CMNETs, but for security measures very powerful CMNET network, this It will be very difficult. 3.3.2 identity ** and password certification system use IP filtering technology, although some non-CMNET network segments can be prevented from invading, because the system is in GPRS subnet, IP filtering can only play simple security, for those who use IP The illegal users of camouflage technology cannot be identified. Since the system is a professional service system, accessing customers is predetermined, using this feature, we use the user ID and password verification technology in the system, and the client's MAC address and password are stored. The IP filtered packet, then verify its ID number and password. For illegal users outside the system, obtaining legitimate MAC addresses and passwords will be very difficult, so this step is greatly possible to increase the system security. 3.3.3 Data Security Encryption Channel System The standard SSL data security communication protocol establishes an encrypted data channel in the client and server side to ensure the security of private data transmission; the system is implanted with high reliability of high reliability in the application layer, making data High reliability can be obtained when any network error is wrong; the MD5 algorithm generates "Packet Summary" has implemented a digital signature of all sending packets, ensuring the integrity of the data transfer process, preventing data from being tampered with. 3.3.4 Access Procedure Tracking System For all access processes, including user identity, IP, time, digital signature, operation, etc., providing system management personnel with detailed, complete and effective operating proof.
The fourth part of the mobile tariff standard and equipment cost 1, the service includes accounting fee, installation of commissioning fees, GPRS special network usage fees, and tariffs that generate traffic using GPRS. 1) Special Internet accounting fee and installation commissioning fee (special network application) account fee: 1000 yuan installation commissioning fee: 500 yuan 2) server-side GPRS special network usage fee (private network application) 1000 yuan / month or 10,000 yuan / year, Not limited to the number of terminals; 3) Terminal GPRS traffic tariff (terminal application) monthly fee (yuan) free traffic (MB) exceeding the flow rate (yuan / KB) free package 0 0 0.03 economy package 20 1 0.01 Fashion Package 100 20 0.01 Business Package 200 Unlimited Use
All local mobile companies have different preferential policies, please negotiate with local mobile companies.
2, the device requires a terminal router to be around 5,000 yuan (the customer is selected), each point is equipped with a GPRS wireless DTU, which is about 1800-2500 yuan. Xiamen Sangrong Technology Co., Ltd. Xiamen Saro Technology Co., .ltd Headquarters Address: 6th Floor, Science Park, Kaiyuan District, Xiamen City: Lin Xiangjian hand: 13950074071 Technical exchange: MSN - lxj7871@hotmail.com Headquarters Tel: 0592-5932711, 5931711, 5931722-22 Headquarters fax: 0592-5932722 -16e - mail: lxj7871@163.com Website: http://www.sangrong.com Technical Forum: http://www.sangrong.com/bbs (Technical Market Exchange World).
