Design Of Direct-Actuated Travel Switch Parameter Measurement System Based On Virtual Instrument Technology

The travel switch is a commomly used master controller to realize the equipment function of positioning control, sequence control and limit position protection, it usually pressed by the mechanical parts to achive the on-off operation of control circuit. Therebefore, its performance directly affects the operation sequence and safety of equipment. At present, the operator examin the travel switch with different instruments for detecting the travel switch parameters. The manual measurement requires skilled operators and can not meet the demands of the products inspection in mass production, with process complexity, low efficiency and great impact of human factor.Combining PC with the testing technology, the Virtual Instrument technology has been widely used in various testing systems. It combines the computer technology with the electronics instrument module by special software. With the PC powerful ability of calculation and the instrument module high accuracy of data acquisition, Virtual Instrument can realize date acquisition and motion control by software programming. Virtual Instrument is more flexible to realize all kinds of testing function with lower cost. Especially the National Instrument’s LabVIEW developing platform can integrate the computer’s hardware and software resources very well.This paper introduces a Direct-Actuated Travel Switch parameter measurement system based on Virtual Instrument Technology, which can provide a solution for measuring parameter of Direct-Actuated Travel Switch. Combined With data acquisition module and servo control module, the proposed system is designed for measuring and screening the Direct-Actuated Travel Switch. And the qualification of products is automatically judged according to the measured result. The operator just fix the switch in special clamp and press the start bottom, the system can realize the automation measurement, at the same time, the process and results of measuremement can display on screen.Firstly, the topic source, research background, research status at home and abroad and research significance were introduced in this paper. Secondly, the mechanical structure, operation principle and characteristic parameters of the Direct-Actuated Travel Switch were analysed. The system main function and technique requirement were designed, and the system general scheme was established. Thirdly, the hardware design which included mechanical structure, hardware selection, control circuit and the anti-interference design was described in detail. Fourth, the design of test software was discussed, including setting module, motion control module, data acquisition module, display module, menu management module, print module. At last, Load sensor calibration and test expriments were introduced. Test data was analyzed to verify the practicality of parameter measurement system. Field experiment shows that the parameter measurement system has a stable and reliable performance with high precision, and the expected technical specifications are achieved.