Application of Beidouxing embedded modem in intelligent electric energy meter

Traditional electric energy meters cannot automatically read and control the user's electricity consumption, which leads to a series of management problems such as difficulty in meter reading and charging, delayed electricity fee recovery, and electricity theft. Magnetic card or IC card electric energy meters use the electricity carried on the card as a benchmark to implement automatic control of electricity consumption, changing the manual meter reading and charging calculation of the electricity management department to the electricity users themselves buying electricity and plugging in the card for electricity consumption, which largely avoids the occurrence of most of the above-mentioned disadvantages. However, since the user's electricity consumption is still isolated from the electricity management department, the management department cannot implement real-time monitoring and management of the user and the electric energy meter itself, and timely discover and solve the problem of illegal users stealing electricity. The traditional electric meter is organically combined with the communication control unit, and the electric energy network management system thus formed can basically cover all the functions required by the electricity management department for the user's electric energy metering device, and can realize intelligent automatic fault diagnosis.

2. Project Description:

The task of this network meter is to accurately reflect the real-time operating status of the user's meter, implement remote fully automatic centralized meter reading, review billing in different time periods and prevent the occurrence of electricity theft, and issue corresponding commands and signals according to specific circumstances to implement remote fully automatic control.

3. Networking devices:

1. Smart meter:

A smart meter consists of three parts: a traditional meter, a signal converter, and a monitoring device.

2. Data collector:

The data logger mainly consists of four parts:

(1) Industrial-grade microprocessor chips are used as core components to manage the entire acquisition control work and run pre-programmed management programs.

(2) Use E2PROM and watchdog circuit to improve system reliability, stability and security.

(3) Use RS485 communication protocol interface to transmit data to the network server.

(4) Pulse signal acquisition and controller interface.

3. Network Server:

The network server mainly collects and stores the data from the data collector. It plays the role of network service in data transmission and is the intermediate bridge for the host computer and the data collector to exchange data. It mainly includes the following three parts:

(1) The main control computer is composed of large-scale, large-capacity memory chips and microprocessors, which complete the storage and processing of all collected data, manage all other components, and run all management programs to coordinate various aspects of the work.

(2) The network management part consists of two major networks:

① Connected with data collector and user query device through RS485 protocol interface, this network is the basic network of this system. It is responsible for the real-time operation of the whole system and has very high requirements on the system, such as anti-interference ability, load capacity and transmission accuracy.

② Public telephone communication network management part. Considering that the network server and the data management center are far apart, we use the public telephone network as the basis for the transmission between our network server and the computer in the data management center. That is, the MODEM interface is set up on the network server to modulate the data signal into the signal of the public telephone network and transmit it to the upper computer (computer in the data management center) which is not in the same location and region. The two parties communicate by dial-up connection, and data transmission is carried out after the connection. In this way, an ordinary computer can be connected to multiple network servers in a time-sharing manner to achieve the purpose of remote automatic meter reading and monitoring of all users.

(3) Data transmission module:

Beidouxing Digital BDXMD-1 embedded industrial-grade MODEM: stable performance, low bit error rate, not easy to drop the line. The appearance is half the size of a business card, which can be easily embedded in various single-board computer systems, saving users' system space. DC5V power supply, TTL level interface, parallel bus and standard serial bus two connection methods, by connecting to the local telephone network or the internal telephone line of the unit to realize remote data transmission and control functions.

4. User query device:

The user query device is the first layer of the human-machine interface, through which the network system can be queried, set, monitored and controlled.

5. Host computer:

The host computer is the second layer of the human-machine interface, which allows managers to monitor the operation of the entire system and issue control commands. It uses a microcomputer, a MODEM, and a dedicated application system window platform to manage and monitor the network system, save and query meter data, automatically generate and print reports, and provide system help instructions.

4. System Implementation:

5. Network Electric Energy Meter Management System Using Power Line Carrier

1. System design:

The system formed by replacing the RS485 protocol communication network with a power line carrier network is basically the same as the above-mentioned network management system in terms of overall structure and principle. The difference is that the aforementioned data collector is installed inside the meter from the outside, and the communication chip, smart meter and user query device communicate with the network server through the power line carrier protocol interface (rather than the RS485 communication protocol interface). Its function and test structure are exactly the same as the system formed by the aforementioned RS485 protocol communication network. Moreover, the number of smart network meters and user query devices connected to it is only limited by the capacity of the network server. However, its on-site installation and construction avoids the trouble caused by the inconvenience of wired connection. Embed BDXMD-1 into the network server, and communication with the host computer system can be achieved through the public telephone exchange network.

2. System implementation: