What Is an Automatic Meter Reading?

Automatic meter reading ^[1] (automatic meter reading-AMR) is a set of computer technology, communication technology, electricity consumption and metering technology. It uses microelectronics and computer networks to automatically read and process meters. A system for comprehensively processing water, electricity and gas information of urban residents. It has the advantages of fast copying speed, high calculation accuracy, good simultaneous meter reading, and direct networking with business computers. The use of an automatic meter reading system can alleviate the labor intensity of meter readers and reduce meter reading errors caused by human factors.It fundamentally solves the troubles caused by household meter reading charges to users and meter readers, and avoids many unnecessary Disputes can not only improve the efficiency of management departments, but also meet the needs of modern users for payment of water, electricity and gas.

1. The acquisition control terminal collects the meter pulses in real time;

2. Use decimal notation, real time

The most common remote automatic meter reading system is the centralized meter reading method of the split line system, that is, the data collector collects the data of one or more meters for processing and storage, and the data collectors are connected by bus. Finally, it is connected to the centralized controller and remotely transmitted to the computer through Modem. However, in the actual application process, it is not the same, and many application methods are derived from it. There are the following types ^[1]

Wireless automatic meter reading ^[2]

"Automatic Meter Reading System Part 1: General Principles" (GB / T 19882.1-2005) "Automatic Meter Reading System Part 1: General Principles" was implemented on April 1, 2006. ^[3]

DL / T698-1999 "Technical Conditions for Centralized Meter Reading System for Low Voltage Power Users"

DL / T645-1997 "Communication Protocol of Multifunctional Energy Meter"

DL / T533-1997 "Technical requirements for radio load control two-way terminals"

DL / T721-2000 "Remote terminal for distribution network automation system"

Real-time meter reading function: real -time reading of the current data and working status of any household meter or all household meters.

Automatic time adjustment function: the system can automatically calibrate the system time when reading the meter.

Disconnection detection function: When the signal line or communication line is disconnected, the system reflects the status.

Gas alarm function: collect the gas alarm signal and display the alarm room number on the computer of the main control center.

Alarm cut-off function: The valve will be closed automatically when the gas alarm occurs, and the computer can also remotely open or close the valve when there is an abnormal situation.

Power-off data protection function: When the system or device is powered off, the data will be stored for a long time.

Cost calculation function: Automatically calculate user fees based on the rate set by the administrator.

Data management function: initialization, statistics, query, report, etc. of user usage data.

System management function: manage system parameters (such as rate, payment method, etc.), administrator operation authority.

Charge collection function: If it is paid manually, the operator will enter the user's payment amount into the computer and archive it according to the charge voucher. If the transfer is charged, the computer will automatically settle the charge. If there is a balance after settlement, it will be automatically accumulated into the next fee.

Report printing function: print various reports as required, such as monthly reports and collection notes.

485 bus mode

The system consists of a master station, a concentrator, a collection terminal, and an electricity meter.

along with

At present, many gas companies in China still use manual meter reading for pipeline gas metering. Not only do companies need to be equipped with a large number of meter readers, but also user arrears and artificial gas theft occur from time to time, causing certain economic losses to gas companies. With the improvement of people's living standards and the development of electronic and communication technologies, manual meter reading has not met the requirements of social development. Implementing automatic meter reading for gas meters is an inevitable trend in the development of the gas industry. Existing automatic meter reading systems use different communication methods. The common communication methods are analyzed below to determine the best communication method of the automatic meter reading system. ^[7]

Automatic meter reading wired communication

Among the wired communication methods, according to different transmission media, there are commonly used communication methods such as power line carrier, LANWORKS bus, RS485 bus, dedicated cable, remote dialing.

Power line carrier is to use power lines to make communication lines, eliminating the need for wiring. The low-voltage power line carrier communication system POWERNET developed by the British remote automatic meter reading company has functions such as automatic meter reading and user management. However, carrier communication has poor reliability, unstable communication, and poor transmission performance, mainly manifested in high noise, low impedance, large loss, large fluctuations, and susceptibility to external interference. If the medium used in the power line carrier is not strictly checked, the probability of data error is very high; if the medium is strictly checked, real-time performance is difficult to guarantee. Therefore, it is not suitable for occasions with high real-time requirements.

RS485 bus is a widely used two-way industrial control bus with a compensated transmission line standard, which can easily form a point-to-multipoint or multipoint mutual communication network. The maximum bus length of each segment is 1200m, each segment supports a maximum of 32 nodes, and a single set of twisted pair two-way master-slave communication. The number of nodes connected on the bus varies with the interface driver chip selected. When the bus lengthens or the number of nodes increases, repeater connections are required. The entire network supports a maximum of 256 nodes. This interface has the ability to suppress common mode interference, so it has reliable performance and strong anti-interference ability. The signal transmission frequency can reach up to 10MHz, and the cost is low. The disadvantage is the need for wiring. RS485 bus has mature application technology in China, so there are many engineering examples of using RS485 bus for communication. The lower communication method of the HG2000A type automatic meter reading system adopted by Shenzhen Gas Group Co., Ltd. uses the RS485 bus, and the system runs stably, but the upper communication method of the system is not perfect.

Adopting special cable communication, the construction cost is relatively high, it is necessary to lay a line, and it is too limited by the region. This method is rarely used due to difficulties in laying cables in the old city or the cables that have already been laid are easy to be destroyed, etc., and has been gradually changed to other communication methods.

The remote dialing method is to use a telephone line or fiber optic cable as the communication medium and establish a connection using a modem. This method is not limited by region, and data collection and communication can be performed at any place and site. The disadvantage is that the telephone line communication speed is slow, if it is through the public telephone network, the running cost is higher. The RS remote meter reading system developed by Shenzhen Runsheng Century Information Technology Co., Ltd. remotely dials through a modem and connects to the concentrator via the facility network to configure the parameters of the gas meter, check the operation of the gas meter and remote automatic meter reading Wait. However, this communication method makes the system operating cost higher, and the telephone line dial-in access only supports polling, the monitoring range is small, and the real-time and anti-control are poor.

Automatic meter reading wireless communication method

Most wireless communication methods use wireless digital radio stations as communication equipment. The advantages are large coverage area, flexible layout, and low operating costs. The disadvantages are poor reliability, high bit error rate, and the bit error rate is directly proportional to the communication rate. The higher the bit error rate is. Therefore, the combination of error detection technology and error correction technology is needed to improve the accuracy and reliability of data transmission to a certain extent. In addition, the communication baud rate is limited by the radio and modem. Therefore, although this method is convenient, its application is limited due to restrictions on frequency bands, propagation ranges, and the influence of urban high-rise buildings on signal propagation. Not many companies use this method to communicate in gas automatic meter reading systems.

Other wireless communication methods, such as satellite communication, microwave, and radio public frequency bands, are also less commonly used in gas automatic meter reading systems. In addition, these transmission methods also have problems such as high investment costs, complex networking work, system instability, and large amounts of maintenance.