Design And Programming Of Host Software In Grounding Grids Corrosion Diagnosis Automatic Test System

To improve the working efficiency, reduce the manpower and increase the data accuracy of grounding grids corrosion diagnosis, an automatic test system is designed and studied , which consists of the host computer, the intelligent DC current source, the 6-and-a-half byte programmable and controllable digital multimeter and the program controlled switching device.As for the host software design of test system, serial communication module, test scheme input module and data processing module are designed and developed. The communication protocol between the host software and the switching device is established. The protocol defines the data format and the verification process. An half-byte exclusive-or checking is used in the verification process, which is improved to enhance the error-detecting capability. The application of RS-232 serial port can realize the communication among the host, the switching device and the digital multimeter. The host of the proposed system sends the control commands through SIO to the switching device to switch the position of the current excitation and the voltage measurement, collecting a series of test data through the digital multimeter.The input module of test scheme can map the original scheme and divide a large scheme into several sub-schemes. As for each sub-scheme, the position of excitation and measurement should be manually arranged beforehand. So as to realize the measurement by shifting the positions automatically. The data processing module can gether the data from the digital multimeter and commit a linear curve fitting on them to reduce the effect of the testing errors in the data.An exprimetal grouding grid with sixty branches is automatically tested and diagnosed to check the developed software, the results of which show that the software is feasible and that it not only considerably reduce the workload, but also avoid the mistakes caused by frequently changing the line connections manually. Further more, linear curve fitting approach of the collected data can remarkably improve the accuracy of the grouding grids corrosion diagnosis.