| This paper presents an embedded multi-channel IP Power Meter which could be used to measure key parameters of single-phase or three-phase AC through network. Using the ARM9 S3C2410 and the ARM7 ADuC7022 as the master MCU and slave MCU respectively and the embedded Linux OS as the operating system, the power meter could be used to measure electric parameters such as the voltage, current, power and power factor for multiple instruments simultaneously. In the mean time, the system can be monitored via network and display, analyze the electric parameters, save the history data in SD card automatically. In order to improve the accuracy and enlarge range of the measurement, the sampling circuit scheme is optimized by removing the sample-and-holder and sampling the current with the two different amplifiers. Moreover, the circuit for periodic interruption is improved to debase the noise in the low-cost hardware scheme, and the interruption priority has been assigned reasonably to get precise watt and power factor result. Random errors are reduced by the algorithm averaging the sample values, and phase difference is compensated by adjusting the relative relationship of the sampled voltage and current value. The performance of the IP power meter is verified by software simulation and sufficient experiments.With the design of multi-channel measurement and SD memory cards, the optimization of hardware and firmware, the power meter which is proved to be low-cost,convenient,accurate is believed to be useful in the remote monitoring and automated systems.
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