Design On Testing And Control System Of High-Density Electrical Equipment

The high density electrical method essentially is belonging to the resistivity methods,it is based on the differences in the electric,study in the artificially applied electric field,the of conduction current in underground distribution。In the design of high-density electrical instrument measurement and control system ,consists of main and auxiliaries of two parts。The main part including upper software,reception and processing circuit of the collection signal and communications part,sending control commands to the auxiliaries part,receiving feedback signal of the auxiliaries part, and so on. The auxiliaries part receive the work orders from the main part through the communication interface,send the measurements to the main part to receive and storage. The main part send the measurements to the upper software to do data processing。The hardware of the main part including the front-end processing module, data acquisition module, control module and communication module . In the first measurement,the collection of data was transmitted to the upper software to calculate,it is mainly to complete the grounding resistance and high voltage calculation to complete the grounding resistance measurement and calibration,it is the zero alignment ,and select the appropriate magnification. Then can carry on the normal gathering work. In the data acquisition module,To separate the signal under the noise environment,first used the instrument amplifier in the circuit design. Because the existence of power frequency disturbance,we use the frequency notch filter in the main engine filter part's circuit design. Then processing the signal to the range of ADC AD7705 ,which owns a programmable amplifier,change the analog signals into digital signals. The converted digital signal processing through the MCU MSP430F1611,and through RS232 serial communication transmitted to the upper data processing software。In the design of the electrode from the machine only more than one core cable, connected between the electrode,that is the concatenation of the form from the machine to connect,will cover the measurement section,this will make it very time flexible. And because the system automatically from the machine for each number, the system can automatically detect all the faults and the location of electrodes.The analog signal processed by the front-end analog circuit need to go through A / D conversion ,and then can do the data processing and display,and the resulting digital signal should be processed through the MCU's internal data processing,these all have to rely on software to achieve. First, Call the initialization function of the underlying software to do the initialization of the corresponding of MSP430 microcontroller port, A / D and serial communications portion ,Require the software in the system initialize the upper set based on the actual situation,such as, select acquisition parameters, set the serial transmit data parameter, and so on. After initialization,After receiving the upper software start command, the MCU controls A / D to do data acquisition,taken up the data spread to the upper data processing software. Because the MSP430 MCU is a function of the processor line programming,so use the IAR Embedded Workbench (V3.42A) as a software development platform,and using the modular design. at the beginning of the program, first do the initialization settings of the first module of the system,to enable them to enter the normal working state,and then testing whether the grounding electrode well,send first measurement data to the top software to do the zero alignment, calibration, etc. After the end of such work, start to do the normal data collection and initial processing, And the measured data transmitted to the top software for data processing and data storage. In the actual measurement process,tested signal is often limited by the potential and frequency interference, led to the change of its characteristics. Therefore, the main purpose of the data processing software is to prevent overshoot and other random disturbances of the environment. Requirements based on the actual situation,Data processing module divided: overshoot removal and digital average two parts。But the top software and microcomputer communications has no corresponding agreement,so designers need to define the actual needs of their command format。In my design,I frame the beginning and end of a fixed format,and by changing the contents of the middle to change the command content. The whole system design is based on virtual instrument technology,applied LabVIEW in the upper formation functional software design.After completing the above work,I do the high-density electrical apparatus for performance testing and laboratory model experiments, and made a corresponding analysis. Completed tests and experiments include, system noise test, minimum resolution test, notch Filter Performance Test, ground Resistance test, standard signal testing and laboratory flume experiments. These experiments and experimental results show that this design can meet the high-density electrical requirements in practical applications.