详细介绍(introduction)：

       DDY79-S型电子式单相IC卡预付费电能表是我厂研制开发的集电能计量、负荷控制和用户信息管理等多种功能的新一代产品。其电能计量部分采用本厂成熟的电子式电能表技术，整体结构合理、工艺先进、并具有电子式电能表的各种优点。在设计过程中，该表充分考虑到在线仪表的特点，在防止掉电、过压、可靠性和抗干扰能力方面采取了一系列措施，完全符合电磁兼容性要求，产品各项性能指标符合国家标准GB/T18460.3- 2001《IC卡预付费售电系统第3部分：预付费电度表》和国家标准GB/T17215-2002《1级和2级静止式交流有功电能表》。
该产品具有体积小、功能全、可靠性高等优点，是当前改革用电体制、实现电能商品化、解决收费难和实现用电监控及调节电网负荷状态的理想产品。

 结 构：

　■ 表壳采用密封防尘防水结构，阻燃、抗老化。
　■ 1只红色LED灯指示电量脉冲，电表每累计一个脉冲当量的电能时，脉冲灯闪烁。
　■ 电表IC卡插座在小门内，具有自保护功能，插卡时小门打开。
　■ 一路光耦隔离脉冲输出，输出宽度约为80ms，供校验使用。
　■ 电量显示采用LED数码管方式，剩余电量等于报警电量时，LED数码管常亮，提醒用户及时购电。
　■ 采用IC卡作为电量传递介质。IC卡经过加密运算，一户一卡，互不通用。
　■ 采用铁电存储器，数据保存可靠。
　■ 采用大容量磁保持继电器，低功耗高可靠。
　技术参数:
　■ 额定电压(V)：220
　■ 工作电压范围：70%Un～120%Un
　■ 额定电流(A)： 5(20), 5(30),10(40)
　■ 额定频率(Hz)：50
　■ 准确度等级：1级，2级
　■ 功耗：电压回路≤2W，10VA；电流回路≤1VA
　 ■ 工作温度(℃)：-25～+55，极限工作温度(℃)：-45～+70
　■ 相对湿度：≤75%（年平均）
　■ 显示范围：0～9999kWh
　■ 数据保护：断电后数据保存时间＞10年
　■ 外形尺寸（mm）：
　■ 平均使用寿命（年）：＞10

　功 能:

　■ IC卡预付费用电，用电量递减。
　■ 剩余电量不足报警，剩余电量为零或到达设定的赊欠电量值时，跳闸断电提醒用户及时购电。
　■ 超负荷时自动断电。
　■ 具有数据回写功能。
　■ 能显示剩余电能量以及其它各种信息

　适用范围:

  ■ 220V 5(20)A----10(40)A为直接接入式仪表，适用于在实施或将要实施预付电费地区的城、乡居民照明计费用表。

DDY79-S Static Single-phase Pre-payment Watt-hour Meter
Main Features
■ Using IC card; Having compositive functions of energy measurement, load monitoring and information management
■ Reasonable structure, advanced craftwork; strong anti-jamming ability; high reliability; design against voltage-interruption and over-voltage, small volume, multi-function
■ Meeting the electromagnetic compatibility requirement
■ Ideal products for energy monitoring and load adjustment of electricity network
■ All specification meeting standard GB/T17215-2002 (IEC61036-2000)on alternating current static watt-hour meters for active energy (classes 1 and 2), GB/T18460.3- 2001 on pre-payment vending system using integrated circuit (s) cards with contacts--part 3: Pre-payment electricity meters.
Structure
■ With sealed case of flame-retardant、water-proof, rust-proof and anti-aging
■ One red LED indicating power pulse and flashing once per pulse
■ Socket for IC card is designed in a small door with self-protective function; Open the door to plug the card
■ One channel of optical pulse output for calibration with width of about 80ms
■ Displaying energy by LED. When remaining energy reaches the alarm quantity, LED flashes.
■ Energy quantity is transmitted through encrypted IC card
■ One card for one meter
■ Adopting FeRAM (Ferroelectric random-access memories) to ensure reliable storage
■ Large capacity magnetic-holding electrical relay, lower power consumption, high reliability
Technical Parameters
■ Rated Voltage (V): 220
■ Operation Voltage (v): 70%Un~120%Un
■ Rated Current (A): 5(20), 5(30), 10(40)
■ Rated Frequency (Hz): 50
■ Accuracy: class1, class2
■ Power Consumption: voltage circuit:≤2W/10VA;　current circuit: ≤1VA
■ Ambient Temperature(℃): -25~+55，limits of temperature(℃)：-45~+70
■ Relative Humidity: ≤75% (annual average)
■ Range of Display:0~9999kWh
■ Data can be stored for more than 10 years when power off
■ Size（mm）：
■ Life(year):＞10
Function
■ Prepay the energy to be used with IC card and the remaining energy will reduce continuously
■ When there is not enough remaining energy, meter will alarm. When the remaining energy reaches zero or one specified quantity, power supply is cut off to remind the user to buy energy.
■ Automatically cut off power supply when overloaded
■ Able to write back data
■ Able to display remaining energy and other information Scope of Use
■ 220V 5(20) A----10 (40) A is for direct connected meters suitable for residential energy measurement at urban or rural areas where energy prepayment has been or is to be realized