The Research On Instrument Control Commonality Technology Of EMC Test System

EMC testing is the most direct and effective method for evaluating the electromagnetic compatibility of various types of electronic systems.Using automatic test systems can not only improve test efficiency,but also reduce the error caused by human factors.However,due to the differences between the instrument's program control instructions and the internal data algorithm of the instrument,if the test instrument in the EMC test system is replaced,the entire test program needs to be recompiled,which often results in many different automatic test software versions for the same EMC test item.Therefore,how to realize the universal control of the instrument in the test system is the urgent and frontier research direction in the field of current automatic testing.This article as a subject to carry out the EMC test system instrument control commonality technology research,designed to achieve the EMC automatic test system for different types of test instrument commonality control,after changing the test instrument does not change the test system's main program.Realize the commonality and interchangeability of measurement and control instruments.This article takes the characteristics of EMC testing as the entry point,standard tests,field tests,and other conventional electromagnetic compatibility tests are classified and summarized,mainly for the three typical pulse signal waveform characteristics and frequency domain characteristics of the electromagnetic pulse time domain test.After analyzing the working principle of each test instrument,the general control flow of the test instrument and the key parameter settings affecting the test result were studied in detail,which laid the foundation for realizing the control commonality of different types of instruments.The premise of realizing the commonality of instrument control is to use universal control bus and interface communication functions.Compared with the GPIB and USB general control bus,the LXI bus has many advantages such as higher data throughput,longer transmission distance,smaller volume and lower cost,and it supports almost all instruments on the market and is the mainstream control bus for instrument control in the future.Based on the functions of LXI bus and VISA interface,this paper proposes the general control principle of EMC test instruments: separately compile the control moduleof the instrument and pre-package the corresponding program-controlled bottom instructions of different instruments;at the same time,adopt the general data processing algorithm independent of the instrument.When changing the test instrument,the test program will actively identify the currently connected instrument through the instrument self-check query command,and then automatically select the corresponding program control instruction after making the judgment,so as to realize the commonality of the entire program control module and the interchangeability of the instrument.When the new instrument is added,only the control instructions of the new instrument can be added into the existing program control module control.Taking the general control of the oscilloscope as an example,the design and development process of the general OCX control is described in detail.Finally,based on the analysis of electromagnetic pulse time domain test,a typical pulse protection universal test system is designed and developed.The design process of the automatic test software is introduced in detail,and the universal control of two digital oscilloscopes from R&S and Tektronix is realized.The application perspective verifies the feasibility of instrument control commonality.