The ADE7878 is a high accuracy, 3-phase electrical energy measurement IC with serial interfaces and three flexible pulse outputs. The ADE7878 incorporates second-order sigma-delta (Σ-Δ) analog-to-digital converters (ADCs), a digital integrator, reference circuitry, and all the signal processing required to perform total (fundamental and harmonic) active, reactive, and apparent energy measurement and rms calculations, as well as fundamental only active and reactive energy measurement and rms calculations. A fixed function digital signal processor (DSP) executes this signal processing. The DSP program is stored into internal ROM memory.
The ADE7878 is suitable for measuring active, reactive, and apparent energy in various 3-phase configurations, such as wye or delta services, with both three and four wires. The ADE7878 provides system calibration features for each phase, that is, rms offset correction, phase calibration, and gain calibration. The CF1, CF2, and CF3 logic outputs provide a wide choice of power information: total active, reactive, and apparent powers, or the sum of the current rms values, and fundamental active and reactive powers.
The ADE7878 contains waveform sample registers that allow access to all ADC outputs. The device also incorporates power quality measurements, such as short duration low or high voltage detections, short duration high current variations, line voltage period measurement, and angles between phase voltages and currents. Two serial interfaces, SPI and I2C, can be used to communicate with the ADE7878. A dedicated high speed interface, the high speed data capture (HSDC) port, can be used in conjunction with I2C to provide access to the ADC outputs and real-time power information. The ADE7878 also has two interrupt request pins, IRQ0 and IRQ1, to indicate that an enabled interrupt event has occurred. For the ADE7878, three specially designed low power modes ensure the continuity of energy accumulation when the ADE7878 is in a tampering situation.
The ADE7878 is available in a 40-lead LFCSP, Pb-free package.
- Energy metering systems
This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.
The ADE7878 is a high accuracy, 3-phase electrical energy measurement IC with serial interfaces and three flexible pulse outputs. The ADE7878 incorporates seven ADCs, reference circuitry and all signal processing required to perform total (fundamental and harmonic) active, reactive and apparent energy measurement, fundamental active and reactive energy measurement and rms calculations.
This documentation describes the ADE7878 evaluation kit hardware, firmware and software functionality. The evaluation board contains an ADE7878 and a LPC2368 microcontroller. The ADE7878 and its associated metering components are optically isolated from the microcontroller. The microcontroller communicates with the PC using a USB interface. Firmware updates can be loaded using one PC com port and a regular serial cable. The ADE7878 evaluation board and this documentation, together with the ADE7878 data sheet provide a complete evaluation platform for the ADE7878.
The evaluation board has been designed so that ADE7878 can be evaluated in an energy meter. Using appropriate current transducers, the evaluation board can be connected to a test bench or high voltage (240Vrms) test circuit. On-board resistor dividers networks provide the attenuation for the line voltages. This application note describes how the current transducers should be connected for the best performance. The evaluation board requires two external 3.3V power supplies and the appropriate current transducers.
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Recommended External References
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(Reprinted with permission from Metering International where it was first printed in Issue 3, 2003)
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.