Smart pre-paid meter

Abstract: This paper introduces single chip design using AT89c52 prepaid watt-hour meter single phase. On the voltage and current collection, computing power, data storage, display and system control and other aspects were introduced. Also gives the hardware schematics and software flow chart, the working principle of each module is analyzed.

Abstract: An electric meter with prepary in single-phase based on the AT89c52 single-chip was designed. Measurement of voltage and current, calculation of electric energy, store and display of date and control of the system was described in this paper. Principle working chart of hardware have been indicated. Soft ware flow chart of the control system was also gived.

Keywords: IC card, energy metering, prepaid, power meter
Keywords:: IC card, measurement of electric energy, advance payment, kilowatt-hour meter

0 Introduction
Traditional meter reading meter regularly need to take the data copied from house to house, clearing out the charges, then each request, the error is large, large amount of statistical work, human error to the power sector and caused great inconvenience to users, but also created users and the electricity sector disputes.

With the city's economic development and improve people's living standard, extensive use of household appliances. Meter reading difficult, troubled power sector hard charges, meter reading personnel to improve the electrical Industry, increasing the company's operating costs, but also brings to the management a lot of trouble, causing a huge waste of human resources, to solve this problem, people start thinking about ways to solve this problem, so the meter IC card, came into being. its momentum of rapid development, unstoppable.

IC card prepayment meter successful Application, to control dual power and energy saving effect, the reform of the consumption pattern followed for decades, that is paid after the first power mode, and after the purchase of electricity to recharge before consumption mode instead. As a user, with a few clear, no longer on the amount of neighborhood conflicts occur, but also did real-time control, as a manager to resolve the meter reading difficult, troublesome accounts, fees and a series of difficult headache problem, as the electricity sector, the advance recovery of investment, improve management efficiency, the country. if the collective consumer groups, also use the smart IC card table, managers will no longer be difficult for the fees, not to bother sharing, provincial heart and effort, with less.

This article describes the use of a single chip controller IC card as a prepaid watt-hour meter. Its development has been widely used in social life, has brought convenience to people's lives. Meter for energy measurement tool, in the National economic sectors has been widely used. has long been used in mechanical induction watt-hour meter. It has a power consumption and more cumbersome and requires manual meter reading anti-tamper performance and low defects. With the rapid development of microelectronics, micro- controller (MCU and large-scale integrated circuits in the field of energy metering a wide range of Applications, so that the level meter technology has made rapid progress.

Although just an ordinary pre-paid meter measuring equipment, but due to the introduction of micro-controller, we design the circuit for the high demands put forward [1]. At the same time as an intelligent home electrical, but also to bring people's lives many of the facilities, which will undoubtedly promote its continuous innovation.

1 System components
1.1 The key performance indicators Accuracy: 2.0, Rated voltage: single phase AC220V, rated current: 5 (20A, 5 (30A, 10 (40A, working Voltage: single phase AC220V, + -20%.

1.2 The schematic diagram of the signal acquisition program with power accumulation-type, before the port current and voltage into the analog multiplier multiplied by an analog voltage proportional to the power P, and then through the V / F conversion into frequency signal f. f microcontroller accumulates the frequency signals can be power. system block diagram shown in Figure 1. This program on low CPU requirements, the use of MCS-51 series microcontrollers fully qualified. And, now has an analog multiplier integrated circuit , low-pass filter and V / F converter integrated with, its performance is far higher than the discrete components. which, analog multiplier, low pass filter and V / F converter integrated circuit SM9903. significantly reduce the number of the device, and CPU use AT89c52, it has 8KB of internal program memory, larger storage space. using liquid crystal display, can greatly reduce power consumption, and can display Chinese characters, so that clarity of the interface [2].

Links to Research Papers Download http://www.hi138.com 1.3 The design of the overall program design energy measurement systems, measurement circuit SM9903, CPU use AT89c52, using liquid crystal display is SMG12232B-2, pre-paid card system sale of electricity as a transmission medium, using the memory card, Atmel AT24C01. over the choice of chips, with VisualC + + on PC preparation of the corresponding point of sale management system, together with the corresponding IC card reader to achieve the initialization , card identification, recharge and other operations. These programs and the choice of components, starting from the practical and economic costs to meet the design requirements [3]. system block diagram shown in Figure 2. Based on AT89C52 microcontroller as the main control components, systems There are energy measurement circuit, control circuit, display circuit, driving circuit, IC card interface, energy storage circuit, power failure detection circuit.

Software Design 2
Main program flow chart shown in Figure 3, the beginning of the first IC card is inserted on whether to judge, when a card inserted, on the IC card to do some judging and handling, when the time is not inserted to determine whether there is a corresponding the button is pressed, a key is pressed when the corresponding keys to read and display accordingly, when there is no button pressed, display the contents of the corresponding [3].

3 Conclusion
The system uses a small device, the circuit is simple, low cost, on the Application of the electric elements and high control accuracy and great use of space, can well meet the requirements of today's living. In the last century or three decades, intelligent With the technological progress of electrical and began to gradually rise into the millions of households, IC card to enter the Chinese market, its existence and development of more and certainly by most people. But there are indications that, with further economic development, living standards improvement in communication technology, network technology, the media Industry and the rapid development of high degree of integration, digital home will be further rapid increase, technology will further mature, all kinds of communications standards and the market will be further standardized, in the near In the future, intelligent machines will be poured into the homes of ordinary people, to people's lives with endless fun.

References:
[1] Peng is, and so on. Microcontroller fine examples of typical design solutions [M]. Electronic Industry Press, 2006.

[2] He Limin. Microcomputer Application system design [M]. Beijing Aerospace University Press, 1990.

[3] Zhou Deming. Microcomputer Principle and Application [M]. Tsinghua University Press, 2002.

[4] He Limin. Microcontroller Advanced Tutorial [M]. Beijing Aerospace University Press, 2000. Links http://www.hi138.com Research Papers Download