This application note describes a high-accuracy, low-cost power meter based on the ADE7756. The design is for use in the North American 3-wire/single-phase application. This meter may also be used in a single-phase, 2-wire distribution system with a minimal amount of changes. The reference design is comprised of the ADE7756, a microcontroller, LCD display, serial interface, and power supply. The ADE7756 is designed to interface to a microcontroller through a serial interface (SPI). The SPI port allows the user to calibrate various components of the meter, including gain, offset, and phase errors. The purpose of the microcontroller is to send display data to the LCD and control the various functions of the meter. An EEPROM is used to store various calibration parameters of the meter and store the meter’s data during a power-down. The entire meter is calibrated through an external calibration routine by a PC through an external SPI interface. The ADE7756 is comprised of two ADCs, a reference circuit, and all the signal processing necessary for the calculation of real (active) power. Circuitry is provided to null out various system errors including gain, phase, and offset errors.
The document details a reference design for a single-element, Class 100 watt-hour meter compliant with ANSI C12.16 specifications. The system utilizes the ADE7756 chip interfaced to a microcontroller via an SPI port, along with an EEPROM for calibration storage and an LCD display.
| Accuracy Class | Class 100 meter in a form 2S designation |
|---|---|
| Compliance Standard | ANSI C12.16 specifications |
| Dynamic Range | 500 |
The design is for use in the North American 3-wire/single-phase application.
Yes, it can be used with a minimal amount of changes.
The ADE7756 interfaces to a microcontroller through an SPI port.