Research on Performance Test of Metering Chip

For testing metering chip’s function and performance, this paper has build a testing platform and done a lot of research, including testing dynamic range methods, reliability and security of metering chip. The error caused by other components is eliminated in this paper in this platform, comparing with traditional meter testing method. The testing platform can load various packages chips from various brands, and be able to not only evaluate performance of metering chips from different manufacturers, but also apply to function and performance test on bulk chips. In additional, a testing result of single phase metering chip V9281 is provided. KEYWORD: Metering chip; Testing platform; Dynamic range; Reliability; Security International Conference on Industrial Technology and Management Science (ITMS 2015) © 2015. The authors Published by Atlantis Press 901 performance. To metering chips, that is to say, the linearity and stability of calculation error from the maximum input value reduces to the minimum value of metering chip. 2) Reliability and security test of metering chip. In the view of many design and operation department, the reliability and security of intelligent meter are even more important than metering accuracy. International institution such as IEC, VDE and NCB established a series of standards on the reliability and security of intelligent meter. IEC 60335, for example, it divides the reliability and security into 3 classes: Class A, the reliability and security is completely independent from software; Class B, the software is able to prevent unreliable or unsafe operations; Class C, the software was specially designed to prevent harmful operation. Metering chips is contained in Class B. As to Class B, it is necessary to find cooperation between hardware and software to improve reliability and security of system. It is required to do visiting privilege protection when software test and operate on key hardware devices of the micro control unit(hereinafter referred to as MCU) such as key register, stack pointer register, program pointer register, addressing and data paths, system clock, Non-volatile register and volatile register. Hardware devices themselves need to supply function of validation, warning and system reset to ensure the normal operation of software. As to metering chip, it should meet criterions of reliability test on integrated circuit and test the metering and communication performance of metering chip under boundary conditions of abnormal voltage supply, abnormal external devices, underload/overload, low power factor and harmonic waves according to the specific operating situation. 3 TESTING PLATFORM OF METERING CHIP Except for metering chip, factors of power supply, sensors and PCB design may influence the metering performance of intelligent meter as well. As a result, it is necessary to design a platform which is able to solely load metering chips of various supply voltages in various packages so that we can evaluate the performance of metering chips without influenced by other factors. It is available to complete test on metering chips in different packages with testing circuit board based on design of MCU and kinds of electric components. The tested metering chip is connected to testing circuit through sockets and loading circuit, after that, it will be tested by MCU programmed previously. Testing circuit board of single phase metering chips joint developed by Chongqing electric power research institute is as shown in Fig.1. It contains fundamental function test (testing result output on liquid crystal display), signal-to-noise test of analog-digital converter (hereinafter referred to as ADC) and test of reliability and security under boundary and limiting conditions. Mainly function design is listed as below: Fig.1 Testing circuit board of metering chips 1) In order to test metering chips of various power supplies, a steady DC voltage source which is continuously adjustable from 1.2V to 6V is needed. 2) Aiming at sample input of metering chip of intelligent meter, a steady AC signal source suit to testing board is necessary to generate a 3 phases AC signal whose amplitude and phase is continuously adjustable. 3) Aiming at the output of metering chip of intelligent meter, we need to supply a precision frequency meter to measure the interval between pulse CF outputs of metering chip besides visiting metering data through interface communication, and then calculate the accuracy of metering chip. 4) Aiming at different interface communication patterns of various metering chips applied in intelligent meters (usually universal asynchronous receiver transmitter (hereinafter referred to as UART) or serial peripheral interface(hereinafter referred to as SPI)). MCU is available to control by C program and can output signal of various transmission rate, various communication pattern and signal with communication interferences(such as rag, irregular duty ratio and so on) to communicate with metering chip according to communication protocol of metering chips. 5) In additional, other devices is needed to change the environmental temperature of metering chips so that the influence quantity test of metering chip applied in intelligent meter would be done successfully. 3.1 Fundamental performance test of metering chip Fundamental performance of metering chip contains linearity error and stability error in rated dynamic range. In this test, we keep the input power frequency voltage of voltage input channel at a best