多年来一直专注于工业自动化领域的高品质工业模组全球贸易。我们专注于PLC组件数控和伺服驱动机器故障？购置更换零件？停产设备麻烦？DCS系统PLC系统机器人系统备件解决方案不要犹豫与我们联系！我们可以提供快速和合格的工业备件援助。************************************************************************ABBIEFAN90ABBIEFAN90ABBIEFAN90*****************************************************************************************************2.1单相电能表的系统组成利用MCP3906和AVRMega16设计的单相电能表系统框图如图3所示。图中，MCP3906芯片用于对输入的电压和电流进行计算。将经过高通滤波后的电压和电流信号相乘，得出瞬时功率信号，此瞬时功率经过低通滤波器即可产生瞬时有功功率信号。此信号不含直流偏移分量，但可利用求平均法计算出所需的有功功率输出：然后通过器件的DTF转换器对瞬时有功功率信息进行累加，以产生输出脉冲，此脉冲的频率与平均有功功率成比例，每个脉冲对应于一个固定的有功电量值；再通过AVR单片机对该脉冲信号进行计数，即可得出有功功率的数值；最后通过LCD显示模块显示出来。系统的电能累计分为第一次上电后的连续累计和时段累计两种。时段累计需要对时间进行判断，即如果当前的时间处在某个时段内，则对该时段进行电能累计；否则，不进行电能累计。2.2系统功能模块(1)RTC实时时钟模块时钟是电能分时计量的基础，实时时钟分硬时钟和软时钟两种，本设计选用硬时钟。当前应用较为广泛的时钟芯片有PCF8583、DS1302等。本设计选用DS1302实时时钟芯片来为系统提供时钟，可精确到年月日时分秒。该芯片内置可编程日历时钟和31字节的RAM，工作电压范围为2.5～5.5V，且功耗低。掉电后可由电池供电，其工作寿命达10年以上。(2)LCD显示模块电能表的显示一般可采用段式LCD显示器，这种显示器具有功耗低、寿命长、显示方式灵活等优点。(3)通信接口模块通讯处理模块是电能表系统与外界通讯的模块，这是依据国标规程编写的一个软件模块。该模块包括通讯接收处理、通讯命令处理及通讯发送处理等部分。由于通讯信道有红外信道和RS485信道两个信道，故在通讯时，要由MCU来判断道底使用哪个信道。(4)数据存储模块该功能模块主要由支持I2C总线的可擦写EEP-ROM(AT25C256)和掉电保护电路组成，主要用于存储计算出来的电压、电流、有功等实时值以及每个时段的有功电能值，还有掉电时间记录、电压电流越上下限报警记录和历史记录等等。如果模块掉电，系统中的掉电保护电路会自动切换到后备电池给外部RAM供电，以保证RAM里所有的数据不丢失。(5)电源为确保电能表稳定可靠的运行，电源是电能表设计的一个关键。本设计采用一路9V电源和一路5V电源来分别给AVRMega16和RS485通信单元供电。通信单元、计量单元和MCU之间的通信采用光耦进行隔离，可提升整个系统的抗干扰能力。众所周知，电能表的干扰源主要有电网的电压波动、闪电冲击和变压器产生的电磁感应等。本设计采用压敏电阻来吸收瞬问高压冲击。电源进线处则使用磁环来防止高频电磁脉冲对电路的干扰和破坏。2.3软件设计整个电能表的软件程序由主程序、系统初始化、电量处理模块、数据存储、键盘中断、LCD显示模块、通信模块等组成。通过主程序或通过中断方式可以调用子程序，以实现系统的整体功能。其中主程序可用于完成启动和系统初始化(包括FLASH、RAM、LCD的设置、SCI及RTC等的初始化)，以及判定时段，在LCD上显示电量和时间等。主程序的流程图如图4所示。P0930FHP0930FJP0930FKP0930FLP0930FMP0930FNP0930FPP0930FQP0930FRP0930FSP0930FUP0930FVP0930FWP0930FXP0930FYP0930FZP0930HLP0930HMP0930HNP0930HPP0930HQP0930HSP0930HTP0930HVP0930HXP0930HYP0930WGP0931DMP0931DTP0931GEP0931JDP0931KFP0931KJP0931NCP0931NDP0931NEP0931NFP0931NGP0931QRP0931QSP0931QVP0931QXP0931RMP0931RNP0931RPP0931RQP0931RRP0931RSP0931RTP0931RUP0931RVP0931URP0931USP0931UTP0940AVP0940AWP0940AXP0940BAP0940BBP0940BRP0940BWP0940BYP0940CCP0940CDP0940CGP0940CTP0940CUP0940CVP0940CWP0940CXP0940CYP0940CZP0940DAP0940DHP0940DKP0940DRP0940FDP0940FPP0940FSP0940FTP0940FUP0940GAP0940GCP0940GDP0940GEP0940GFP0940GGP0940GHP0940GJP0940GKP0940GLP0940GMP0940GNP0940GPP0940GQP0940GRP0940GSP0940GVP0940GWP0940HAP0940HBP0940HCP0940HDP0940HEP0940HFP0940HGP0940HHP0940HJP0940HQP0940JDP0940JEP0940JFP0940JGP0940JHP0940JJP0940JKP0940JLP0940JMP0940JNP0940JPP0940JQP0940JRP0940JSP0940JTP0940JUP0940JVP0940JWP0940JXP0940KPP0940KSP0940LWP0940LYP0940MAP0940MBP0940MCP0940MDP0940MTP0940MUP0940MVP0940MWP0940MXP0940MYP0940MZP0940NBP0940NCP0940NDP0940NEP0940NFP0940NJP0940NNP0940NPP0940NQP0940NRP0940NSP0940NVP0940NXP0940NZP0940PAP0940PFP0940PMP0940PNP0940PQP0940PRP0940PSP0940PTP0940PUP0940PVP0950BMP0950BNP0950DAP0950DFP0951APP0951BAP0951BVP0951BXP0951BYP0951BZP0951CBP0951CCP0951CDP0951CEP0951CFP0951CHP0951CJP0951CKP0951CLP0951CMP0951CNP0951CPP0951CQP0951CRP0951CSP0951CTP0951CUP0951CVP0951CWP0951CXP0951CZP0951DAP0951DEP0951DFP0951DKP0951DLP0951DVP0951EFP0951EGP0951ELP0951EQP0951ESP0951ETP0951EWP0951FJP0951FKP0951FLP0951FMP0951FNP0951FPP0951GGP0951GPP0951GQP0951GRP0951GSP0951SDP0951SEP0951SFP0960AHP0960AWP0960GCP0960GXP0960HAP0960JAP0960KAP0960LFP0960MAP0960MKP0960NBP0961AAP0961BCP0961BDP0961BSP0961CAP0961CNP0961CPP0961DHP0961DKP0961DMP0961DNP0961DWP0961EFP0961EGP0961FRP0961FXP0970BCP0970BMP0970BPP0970BVP0970BWP0970BXP0970DCP0970DFP0970DGP0970EJP0970GWP0970HHP0970HSP0970HTP0970HVP0970HXP0970JAP0970JBP0970JDP0970JEP0970JGP0970JHP0970JJP0970JKP0970JLP0970JRP0970JWP0970JZP0970KEP0970KFP0970KGP0970KHP0970KJP0970KTP0970KUP0970KVP0970KWP0970LJP0970LKP0970LWP0970MMP0970MNP0970MUP0970MVP0970MYP0970MZP0970NGP0970NLP0970NMP0970NRP0970PAP0970PBP0970PCP0970PDP0970PEP0970PFP0970PJP0970PKP0970PL)