The Design And Implementation Of A Ground Equipment Based On Multi-mode For Testing The Data Recorder

At present, in order to analyse data and diagnose fault, an increasing number of datarecorders are needed for testing and recording some critical parameters of spacecraft tests.This article is designed for a ground testing device based on multi-mode, to test theperformance of the aerospace data recorder, meanwhile, the design also focus on solvingseveral shortcomings of the existing ground testing equipment: (1) The speed of datalong-distance transmission is so low that it is unable to adapt to the occasion of the high-speedtransmission of large amounts of data; (2) The key control signal from the ground testingdevice to the data recorder is depended highly on the control of PC software, resulting in itspoor reliability.Firstly, due to RS422 interface between the ground testing equipment and the recordergenerally used in a long-distance test in the past, the speed of data transmitting is very low. Inthis design, the interface is changed to LVDS of anti-interference performance perfect anddata transmitted high. Meanwhile, the 8b/10b encoding and decoding during the datatransmitted used, is beneficial to the data transmitted in 50 meters of twisted pair, baud ratesup to 300Mbps.Secondly, with regard to the low reliability of the critical signal between the groundtesting device and the recorder controlled by PC software, the reason is given in this paper,such as communication anomalies of the USB interface caused by noise disturbed, data errorduring the long-distance communication, the system halted and so on, caused the loss ofcritical control signals. In view of this issue, the method put forward in this paper which thesignal of panel switch adopted after eliminated shake of hardware and software is used tocontrol the light relay on and off. In the process of testing, the computer is used to issue somenon-critical command signal, thereby the dependence of the computer for the critical signal and a variety of data interfaces are reduced, and the reliability of the test system is improvedas a whole.In view of the reliability, maintenance and other considerations of the equipment,modular thought is adopted in design, in which hardware and software design process iselaborated detailedly. At that time, some of the problems encountered in circuit debugging andsolution are given, and finally the feasibility of this system is verified through theexperimental data.