Study On The Technology Of Sampling Over-voltage Signal Produced When The Relay Turns Off

The relay being a base electric element, it's life span not only reflects the quality of the relay, but also affects directly the reliability of electric equipment using the relay. The high frequency, large amplitude over-voltage signal produced when the relay turns off is one of the important indexes evaluating the relay.With reference to internal and international correlation research achievement, and by analyzing the technique require to high-speed data sampling system used in relay test, the thesis brings the whole plan forward: The data sampling system is on core of DSP and expands apparatus based on DSP. They form a least system and are made to a high-speed data sampling card. The card is inserted to ISA bus in PC. In this system, it is master-slave structure between PC and DSP. DSP transfers data to PC by adopting the DMAC(Direct memory access controller)in PC. The thesis dwells on every part of hardware circuit and main technology such as DSP, the transferring mode of DMA (Direct memory access), etc Subsequently, it introduces the software design of the sampling system and user interface. Finally, it shows the waveform of over-voltage and current.