A lithium battery in the electronic multi-function meter application since the 1953 introduction of our country from the Soviet Union since the first one meter, then the enterprises directly under the central part of China, and gradually mastered the manufacture of electric energy meter core technology. That is still the planned economy era, but directed the sale, China’s reform and opening up, the economy and the market has set the amount of the original production step by step with market demand as the starting point.
Implementation of state-owned enterprises are contracting system. Personnel reform has also brought some people out of a state-owned enterprises, a number of skilled personnel to form a one meter factory, such examples in a short few years mushroomed across the country, such as the rise. Today, exports are now larger meter plant will have a lot of home: like people, electrical appliances, Jiangsu, Lin Yang, Hangzhou Holley, Henan Xu Ji, Kazakhstan and other table.
Today’s energy meter mechanical watches have been made to the original electronic multi-meter, the following detailed electronic structure and principles of multi-meters: Electronic Energy Meter Three-phase electricity primarily for the domestic market for industrial users. With the power sector reform in-depth, industrial three-phase electricity demand for multi-function watt-hour meter has increased substantially. Currently multi-table type of small, higher-priced, feature incomplete, often only for the specific requirements of the development in some areas, the lack of commonality, some products can not fully meet the national standard requirements.
This article describes the electronic multi-function watt-hour meter precisely in order to meet the needs of this market design. This is an intelligent high-tech energy measurement products, the table can simultaneously measure positive / reverse active energy, positive / reverse reactive power, four-quadrant reactive energy, but also has a multi-rate control, load curve record, the phase loss voltage, over voltage, frequency overrun records, data, lcd displays a variety of functions. Master rs-485 bus through the infrared meter or handheld device to look-up table for the meter, set the table, meter reading, such an operation. The software code used in all c / c + + language, coding, high efficiency, hp 338794-001 battery,hp 361742-001 battery,maintainability is good, is easy to realize modular design, according to the needs of users to easily cut of functional modules. And the code is optimized, the generated object code size and efficiency in the implementation has almost the same with the assembly code.
Technical specifications of the product fully compatible with gb / t 17215-1998 “1-and 2 AC static watt-hour meter”, dl/t614-1997 “Energy Meter” and dl/t645-1997 “multi-function watt-hour meter communication protocol “requirements. Multi-function watt-hour meter and hardware design of the overall structure of the overall structure of multi-sheet multi-function watt-hour meter electronic hardware, the core of mcu master controller, which is responsible for key input scanning, the work of state detection, measurement data is read, computing and storage, meters parameters on-site configuration and control communication with the outside world. Its main function modules include mcu master controller unit, power measurement module, infrared and rs-485 communication module, school table module, eeprom storage arrays, etc.; other auxiliary modules are: clock calendar circuit, the work exceptions alarm circuit, key input circuit, reset and watchdog circuit, switching power supply module and back-up hp 371785-001 battery,hp 372772-001 battery circuits, large-screen liquid crystal display module and the led display modules. Multi-function block diagram of the overall structure of the table shown in Figure 1. High-performance host controller unit master controller nec companies in the high-end 8-bit microcontroller products upd78p0338.
Microcontroller which is 120 feet qfp package, monolithic integrated 60kbflash, an asynchronous communication serial port, 40×4 segment lcd driver, up to 10mhz bus clock and 10-channel 10-bit precision adc, can be a simple The in-system programming interfaces, which greatly facilitate debugging, and software upgrades. And support high-level language, and to better meet the multi-function table many tasks, a large amount of data, the algorithm more complex functional requirements. Serial multiplexing communication unit communication circuit module includes the first tsopl838 infrared receiver, infrared emitting diodes, carrier circuits, max487 exclusive 485 transceiver circuit, driver / switch diodes and other components. This user-friendly meter for meter reading, meter reading and the design of infrared local rs-485 serial meter reading meter reading two kinds of ways, because upd78f0338 only one serial port, so communication circuit design uses serial port multiplexing . From the 9012,9014 and a number of resistors composed of complementary devices such as switches, from the mcu’s an i / o port to control the infrared and rs-485 communication mode switching, as shown in Figure 2. High-precision power measurement module consists of high-precision measurement module dedicated hp 398876-001 battery,hp 417066-001 battery metering chip, sa9904, current transformers, and other external circuit elements formed.
Sa9904 is produced by sames a three-phase bi-directional power / energy measurement IC that can measure active / reactive power, voltage, frequency, phase-sequence anomaly, could be measured separately for each phase of the power of information in line with the standard iec521/1036 can be achieved by an exchange of energy meter accuracy requirement, the data register with 24-bit precision, can be three-wire spi interface to exchange data with the cpu. So you can better adapt to multi-table data need to be measured a variety of power requirements. sa9904 pin and its peripheral circuit shown in Figure 3. Which, clk, do, di composition and mcu controller interface for the transmission of control commands and the measured power data, iips, iipt, iipr be used for current sampling, ivpl, ivp2, ivp3 used to voltage sampling. Clock calendar module clock circuit using epson produced rtc-4553 real-time clock chip. Internal integrated 32.768khz quartz crystal oscillator, to simplify the external circuit, and can be freely set as needed in order to obtain a higher frequency; while integrated clock and calendar counters, hp 346970-001 battery,hp 367759-001 battery,choose 24 or 12 hours display mode, the clock can be software conducted at intervals of 30 seconds to adjust, and provide 0.1hz or 1024hz timing pulse output, so the meter outside of the clock precision of conduct regular inspections. rtc-4553-pin and its peripheral circuit shown in Figure 4. Whether electricity meter or the clock battery meter is also one of the key components.
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