Design of GPRS Remote Meter Reading monitoring system

preface

GPRS Remote Meter Reading and monitoring system can monitor the flow data of electricity in the jurisdiction in real time, monitor the safe operation of the State Grid and power supply equipment, realize intelligent duty, read meters at any time, pay fees and save manpower and material resources. At the same time, it can monitor sudden power supply accidents and assist in analyzing the causes of accidents. Here are some opinions on the design of GPRS Remote Meter Reading monitoring system.

1¡¢ Design scheme of GPRS Remote Meter Reading monitoring system

In the remote monitoring scheme, GPRS communication network provided by China mobile communication is adopted. GPRS is the English abbreviation of general packet radio service. It is a new packet data bearer service. As a 2.5 generation mobile communication technology, GPRS is a perfect solution to solve information transmission by using mobile communication. Compared with the traditional circuit exchange data transmission mode, it has the following key points: always online; Billing by data flow; Short login time; Fast data transmission speed; It covers a wide range and is not limited by distance. The launch of GPRS provides an infrastructure platform for power enterprise users to carry out wireless office, and creates favorable conditions for promoting the application and development of mobile office. The emergence of GPRS also provides a new choice for power enterprises to carry out wireless data management. The system consists of monitoring center, communication network, front-end equipment and monitoring box.

1.1 monitoring center

1.1.1 monitoring center equipment. Industrial computer, display, GPRS data transmission module, switching power supply, UPS power supply (optional), printer. The industrial computer and GPRS module are connected by serial port line, and the operating system software, database software and monitoring system software are installed on the industrial computer.

1.1.2 monitoring center system software. It consists of two parts: monitoring system software (workstation software) and front-end computer software. The monitoring system software is developed by using c# language. The software has intuitive picture and friendly interface. It has many functions, such as data display, data query, alarm display, water resources statistics and curve report generation. The administrator of the monitoring host has the authority to set and modify the rate, update and add new user data, and define the authority used by others. The front-end computer software is a communication management software, which supports various domestic and imported configuration software. It does not need the special driver "click to download" provided by the configuration software manufacturer to use it.

1.2 communication network platform and equipment

The design system relies on the GPRS network of mobile company to realize wireless data transmission. The special line networking mode is adopted, which is suitable for users who have dedicated Internet access, or when the data flow is relatively large and the acquisition cycle is required to be relatively short. The leased line can be the optical fiber connector of China Mobile or the optical fiber connector of China Telecom Netcom. The control center still needs to install a GPRS module, which is mainly to serve users to actively send relevant alarms and important information to the mobile phone through mobile phone inquiry. The GPRS data transmission module produced by Beijing zhongruineng Instrument Technology Co., Ltd. can log in the GPRS network of China Mobile and transmit data on the network. The monitoring center uses a GPRS data transmission module, and a GPRS data transmission module is installed in each front-end device, which can realize the data communication between a monitoring center and multiple front-end devices.

1.3 special monitoring box

GPRS wireless communication module, switching power supply, UPS (optional), etc.

2¡¢ Design example of remote meter reading monitoring system using GPRS

Using the GPRS platform of mobile company as the communication network, the system construction is simple, fast and stable.

2.1 system composition

The system consists of four parts: monitoring center, communication network, monitoring terminal and flowmeter. The monitoring center mainly includes: computer, printer, GPRS data transmission module and stand-alone monitoring system software. Communication network: gprs-vpn roaming network of China Mobile. Monitoring terminal: self powered wireless meter reader (jy-rtu). Electromagnetic flowmeter: RS232 or serial port can be provided.

2.2 main functional features

Real time data acquisition function: collect the instantaneous flow and cumulative flow on site. Real time data display function; Display the instantaneous flow and cumulative flow at the site. (display data through the flowmeter itself) alarm function: communication interruption alarm with the flowmeter and low battery voltage alarm. Storage function: the information of power grid monitoring points, real-time data, event records and operation records are stored in the database. Statistical function: report function: daily report, monthly report and annual report; Curve function: daily curve, monthly curve and annual curve; Query function: power grid monitoring point information, historical records, historical curves, event records, operation records and historical reports; Printing function: power grid monitoring point information, historical records, historical curves, event records, operation records, report forms, security function: password function: password must be entered to enter and exit the system; Permission function: different operators have different functions; User switching: different operators can switch in the system during handover. Extended function: number of monitoring points: users can add or delete. It can support adding one channel of analog pressure signal. Setting function: power customer information input and modification; Collection cycle setting and modification; Remote maintenance function: remotely set the working parameters of the sub station (monitoring point).

2_ 3 technical indicators

2.3.1 working power supply. Jy-rtu wireless meter reader uses two No. 1 disposable lithium batteries and meets the following requirements. 1) Rated working power supply voltage: DC3 6V; 2) Allowable deviation - 10% ¡« + 1o%; 3) Instantaneous discharge current: not less than 2A.

2.3.2 power dissipation. Sleep: the current is no more than 35ua. Working: the maximum current is not more than 500mA.

2.3.3 serial communication interface. 1) RS232, communication distance not more than 20m, RS485, communication distance not more than 200m. 2) Baud rate (1200 ~ 19200bit / s) is optional, check bits (none, odd and even) can be set, 8 data bits and 1 stop bit.

2.3.4 environmental conditions. Working environment conditions: 1) ambient temperature: 20 ~ 70 ¡æ; 2) Relative humidity: ¡Ü 95%; 3) Atmospheric pressure: 79.5 ~ 106.0kpa (altitude 2000m and below). Surrounding environment requirements:

1) Strong vibration and impact are not allowed;

2) Gases and conductive media that corrode metals and damage insulation are not allowed, and media with explosion hazard are not allowed.

3) Strong magnetic interference is not allowed.

4) The mobile network communication signal is good without shielding. Environmental conditions for transportation and storage: 1) ambient temperature: 4O ~ 85 ¡æ; 2) Relative humidity: 95%.

2_ 3.5 enclosure protection grade. Up to gb4942 2 IP68 grade requirements.

2-4 function introduction

2.4.1 setting function.

1) Communication interface type can be set: RS ~ 32, RS485:

2) Communication interface parameters can be set: baud rate, check bit and framing timeout;

3) Reporting methods can be set: SMS and GPRS;

4) You can set the reporting target address: the number of the monitoring center of the upper computer and the monitoring IP address of the upper computer;

5) You can set the time benchmark, collection interval and reporting interval of collection and reporting;

6) Real time clock can be set;

7) Reporting contents can be set, such as cumulative flow, water level, etc;

8) Battery alarm voltage and calibration parameters can be set.

2.4.2 display function. LED displays the functions of operation, acquisition, network data sending and receiving, Internet status, signal strength and fault status.

2.4.3 communication function. 1) Function of reporting data to 1 ~ 4 centers by SMS; 2) The function of reporting data to 1 ~ 4 centers in GPRS mode.

2.4.4 detection function. 1) Check the battery voltage b. Detect the communication status function of external instrument communication interface; 2) CPU system, communication module and memory fault detection function.

2.4.5 alarm function. 1) Instrument communication interruption alarm; 2) Low battery alarm.

2.4.6 timing acquisition function. 1) Start the machine regularly to collect instrument data according to the set time benchmark and acquisition interval; 2) If the first acquisition of instrument data fails, the meter reader will issue the acquisition command again; 3) If no response is received from the third acquisition of instrument data, the meter reader will record the interruption of communication and then shut down automatically.

2.4.7 regular reporting function.

1) Start the machine regularly to report data according to the set time benchmark and reporting interval;

2) Regular reporting by SMS: A. when all history records cannot be carried by one SMS, it can be reported by multiple SMS B "automatically receive and process the data reported by the meter reader after the central monitoring software runs.

3) Regular reporting by GPRS: A. wait for the response of the data center monitoring software after reporting the data, and shut down immediately after receiving the response; b_ If no response is received, it will be re sent twice. If there is still no response from the monitoring software, the meter reader will shut down automatically and report the data next time.