| In this paper, a new electromagnetic environment monitoring system of industrial frequency of city is designed. The system is used to monitor magnetic inductive intensity of electromagnetic environment of transformer substation and high voltage electrical wire in city. The inequiotential voltage and temperature error of the hall component is modified with planar recursive analytical means. It consists of data acquisition network and the inspection software platform for PC.Data acquisition network is built up with many data acquisition terminals. Each data acquisition terminal consists of three sensor-detectors and an embedded data acquisition instrument. Sensor-detector includes sensor module and signal process module. The data acquisition instrument mainly comprises six modules: control circuit, data acquisition (12 bits ADC), data memory (8K bytes RAM and 16M bytes NAND FLASH), communication with PC, clock circuit and power circuit. The data acquisition and data transmission to PC all are programmed with C, as well as data memory.Sensor includes Hall component and temperature sensor. Hall component switches magnetic inductive intensity to hall voltage by hall effection and temperature sensor measures the temperature of work environment of hall component. Then the hall voltage is transmitted to data acquisition instrument after being processed. The hall voltage is switched to digital value and saved in data acquisition instrument for several hours or days, and the switching result in data acquisition instrument can be transmitted to PC with RS-485. Data acquisition frequency is 2.7KHz and communication speed is 115.2Kbps.The inspection platform with Labview achieves management of remote terminals, long memory of measuring data, figure display and result evaluation, etc.Last, some experiments in Dalian verify that the measurement error of the system is not more than 9% after the measurement data of the system compares with EFA-300. |
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