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1. Project background
With the continuous improvement of people’s living standards, the common people have put forward higher requirements for the living environment; inspired by government policies, the intelligent home furnishing has been developed at a high speed. As a link in the intelligent industrial chain, the intelligent meter reading system has also developed vigorously. The traditional manual meter reading method is time-consuming, laborious, accuracy and timeliness cannot be guaranteed, and some unpleasant embarrassing situations will occur between meter readers and users, which is no longer suitable for the development needs of society. This also puts forward higher requirements for meter reading. For this reason, we propose a new meter reading program-wireless meter reading. At present, there are basically two data transmission methods for cell meter reading, wired data transmission and wireless data transmission. If the cable is used to transmit data, the technology is simple, mature, and easy to implement; however, the construction and wiring workload is large, and the network cable is vulnerable to man-made damage. After the line is damaged, the fault point is not easy to find. If you use a wireless system, the construction is very simple, the system is easy to maintain, and the fault is easy to find. Therefore, wireless meter reading will become the mainstream of the development of meter reading methods. This program is mainly aimed at the copying of residential electric meters.
2. System analysis and construction
The construction of the wireless meter reading system is mainly the construction of the wireless network. The whole system is divided into three parts: the data collection part, the wireless networking part and the data management part.
1. Data collection part:
Data is divided into command data and collected readings. The transmission of data in the entire system is in the form of data packets. The transmission direction of the command packet is opposite to the transmission direction of the reading data packet.
Data collection refers to reading the data of the electric meter, and transmitting the data to the data management terminal through a certain transmission method. The data collector is connected to each electric meter on this floor through the RS485 bus. Each collector is equipped with a wireless data transmission module, and the collected data is sent out through the wireless data transmission module. The schematic diagram is shown in Figure 1:
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figure 1
2. Wireless networking part
The wireless networking is divided into two parts of the wireless network: the building internal network and the base station network. The entire network adopts a tree-structured networking form.
The wireless network adopts the networking mode of address association and tree structure. Each data packet has an address, and its address determines the direction of data transmission, whether it is uploading or downloading.
2. The internal network of the first floor:
The internal network of a building refers to the wireless networking between the collectors on each floor of a building. The collectors on each floor send data directly to the base station of the building through a wireless transmission device, and finally the base station sends out the data. If the collector and the base station cannot communicate directly, use relay forwarding. The network follows the principle that the shorter the link, the better. Its data transmission is shown as in Fig. 1.
2.2 Base station network:
The base station network refers to the wireless network between buildings. A base station is installed on the top of each building to transmit data collected in this building and forward data from other buildings. The shorter the network compliance link, the better, and the ones that can be reached directly do not use relays. The schematic diagram of its networking is shown in Figure 2:
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figure 2
2.3 Handheld
The handheld is a bridge connecting the community and the management department. The handheld downloads and saves data from the community main station in a wireless manner, and then transfers the data to the PC of the management part by wire. The management part can also use the handheld to send out at the main station. Commands such as meter reading, valve control, etc., are transmitted to the base station network through the main station until they reach each meter, so that the meter can perform corresponding operations.
Another purpose of the handheld is to set the addresses of all wireless devices in the system.The handheld is shown in Figure 3
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image 3
3. Data management part
The meter reader only needs to download the data to the handheld computer at the main station of each district, and then download the data to the PC through the wire using the hand-copying machine, and the PC can effectively manage the collected data through the database. The management database uses the three-meter data collection and management system designed by our company.
Three, wireless module
The wireless module uses the wireless remote data transmission module ZF-02 independently developed by our company. (The module has an automatic avoidance function. When it detects that a module is sending data, it will not send it by itself. It will not start until no other modules are sending data. The sending function sends the data to be sent to avoid interference.) The wireless module is connected to the collector and the base station, and is used to collect the readings of the electric meter and store it for sending. The module is in sleep state most of the time, but for a period of time. It wakes up automatically at time and detects whether there is a wake-up signal from the outside (mainly used for the collector to copy data). If it detects a wake-up signal, it will be awakened and wait for the next instruction to perform related operations. If there is no wake-up signal, it enters the sleep state again. In this way, the power consumption of the wireless module is very low, and if it is powered by a battery, it can reach 1 to 3 years.
Four, communication protocol
In the system, the communication protocol and data format between the wireless module and the meter are communicated and defined in accordance with “The People’s Republic of China Urban Construction Industry Standard (CJ/188—2004)-Technical Conditions for Data Transmission of Household Meters” .
5. Features of wireless meter reading system
1. The wireless module has multiple channels and multiple baud rates (users can choose); the hardware adopts high-precision integrated packaging technology, with small frequency deviations due to environmental temperature and humidity changes, accurate measurement, and reliable communication; micro power, long communication distance, The price is low.
2. The wireless meter reader is convenient to carry, simple and intuitive to operate, and has rich functions.
3. The system is highly integrated and the total cost is low.
4. Data can be copied at any time.
5. Do not enter the home for meter reading to avoid disturbing the people.
6. With valve control function.
7. Simple system and high meter reading efficiency
Shanghai Zhaofu Communication Technology Co., Ltd.
Dong Jun:13482884948
021-51822510-14
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