Integrated Test Station, Based On Field Bus Technology Pilot Valve

The first pilot valve of electromagnetism is an important part to transforms the electrical signal as the pneumatic control signal. It is widely applied to industrial fields and has wide developing space in war industry. Therefore the quality is the most important question to the first pilot valve of electromagnetism, The first pilot valve of electromagnetism all must carry on four tests when leaves the plant: the DC resistance, Hi-pot, Insulation and Surge. In tradition, generally adopts the manual test, the test efficiency is low and the test result is not unable to satisfy the industrial automation production requests. At present, the text platform of the valve used in China has to be imported and is very expensive. Therefore, it is very urgent to develop the text platform of the valve with the patent of our country. And the significance in economy and stratagem is great. In view of this, the text platform of the valve is carried on the research development. And it adopts the parallel test method, enhances the test efficiency.In the 1990s, some company in Japan assembles a platform using two separate PLC. And it uses the serial communication principle, so the test efficiency is low, the text results is inaccurate and the service not convenient, therefore it basically does not have the effect in the production. In view of this kind of situation.In this paper, we use single PLC according the parallel test principle to control the platform. The test efficiency enhances four times, the test result relatively stable, and matches the requirement of the production.Firstly, the mechanical structure, electro-circuit structure and working principle of the text platform of the valve are introduced in the paper. The scene operation part of the text platform contains the operation board, the outer covering, the measuring instrument as well as the jig part. The control section is composed by PLC, the DeviceNet master station module, the gateway part and the I/O connection part. The gateway is the core of the control section which follows the DeviceNet agreement, and it is the bridge connects the DeviceNet network and the scene operation part.Secondly, there is an introduction for the field bus agreement part, the hardware part and the PLC master station module. Agreement part includes the DeviceNet correspondence function, the object model, the DeviceNet connection and the text of telegram agreement; here we mainly discuss the telegram of the MAC ID inspection. The hardware partial mainly introduces CAN bus control unit SJA1000 and its periphery component, mainly includes the principle of the work of SJA1000, internal register disposition, the filter way and the initialization flow. The introduction of PLC mainly includes how to transform the traditional PLC procedure to which can actuate the gateway module the procedure: The principle is very simple, only must transform the traditional I/O area data to the gateway unit correspondence data area. After had understood agreement content and hardware disposition then starts to carry on the gateway module communication program, compiles the ATmega8515 monolithic integrated circuit procedure using the assembly language for the software carrier, realizes the communication function need.Finally after introduced the reason to carry on Hi-pot, surge text and the experimental parameter request, the research of the platform is particular expounded, including the reason of using PLC, the construction of the hardware electric circuit, the PLC logic control chart and the parallel test principle and its the merit. And has carried on the contrast analysis to the test result, proves the platform is completely conform to the test automation requirement, and made the test efficiency to enhance four times, and through the field bus, the platform can record the test results, print and has long-distance supervisory control function.