The ADE7854A/ADE7858A/ADE7868A/ADE7878A are high accuracy, 3-phase electrical energy measurement ICs with serial interfaces and three flexible pulse outputs. The devices incorporate second-order Σ-Δ analog-to-digital converters (ADCs), a digital integrator, reference circuitry, and all signal processing required to perform total (fundamental and harmonic) active, reactive (ADE7858A, ADE7868A, and ADE7878A), and apparent energy measurement and rms calculations.
The ADE7878A can also perform fundamental-only active and reactive energy measurement and rms calculations. A fixed function digital signal processor (DSP) executes the signal processing. The DSP program is stored in the internal ROM memory.
The ADE7854A/ADE7858A/ADE7868A/ADE7878A can measure active, reactive, and apparent energy in various 3-phase configurations, such as wye or delta services, with both three and four wires. Aside from regular rms measurements, which are updated every 8 kHz, these devices measure low ripple rms values, which are averaged internally and updated every 1.024 sec. The devices provide 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 selection of power information. All four devices provide total active and apparent powers, as well as the sum of the current rms values; the ADE7858A, ADE7868A, and ADE7878A also provide total reactive powers; the ADE7878A also provides fundamental active and reactive powers.
The ADE7854A/ADE7858A/ADE7868A/ADE7878A contain waveform sampling registers that allow access to all ADC outputs. The devices also incorporate power quality measurements, such as short duration low or high voltage detection, short duration high current variation, line voltage period measurement, and angles between phase voltages and currents.
Two serial interfaces, serial peripheral interface (SPI) and I2C, can communicate with the devices. 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 devices have two interrupt request pins, IRQ0 and IRQ1, to indicate that an enabled interrupt event has occurred. For the ADE7868A/ADE7878A, three specially designed low power modes ensure the continuity of energy accumulation when the ADE7868A/ADE7878A are in a tampering situation.