Development Of Signal Integrity Test Platform For Industrial Cable Network Based On PXIe Bus

The cable networks are the main carrier for signal and power transmission between the sub-modules of the industrial system,and its reliability is of great significance for the normal working of the entire system.The traditional testing of the industrial cable networks mainly focuses on the basic functions,such as conduction and insulation.However,the signal integrity problems caused by signal reflection,crosstalk,electromagnetic interference and high-frequency signal attenuation are not fully studied.This makes it impossible to determine the reason of fault in time when an error occurs in signal transmission.In order to solve this problem,this thesis developes the signal integrity test platform based on PXIe bus,which can test and simulate the signal characteristics of different positions i n the cable networks.The test system can quantitatively evaluate the signal transmission integrity indicators of complex cable networks,which provides a basis for the reliability design of the current system.This thesis analyzes the requirements at first and formulates the software and hardware design scheme.The hardware system of this platform takes PXIe bus as the kernel when measuring and controling.The main instruments include embedded controller,remote controllers,digitizers,timing synchronization modules and disk array.The platform adopts the form of multi PXIe chassis cascading,uses the remote controller and timing synchronization module to control and realizes the distributed multi-channel data synchronous acquisition and processing.The software design of the platform is divided into two parts.Firstly,the master control software of the test platform is developed based on Labwindows/CVI software.The NI TClk synchronization technology and multi-threading technology are used to realize the multi-chassis and multi-channel high-speed synchronous acquisition function,and common waveform time-frequency testing methods and eye diagram evaluation algorithms are used to analyze the integrity of the signal.Secondly,the simulation model for the signal’s transmission characteristics in cables is proposed based on the signal transmission line theory and the simulation software is developed.This model combines the mathematical model of signal time domain reflection and the signal amplitude simulation model based on Fourier transform.It is used to simulate the signal transmission characteristics under different positions and different loads of the cable.Finally,this article tests the software and hardware functions and technical indicators of the signal integrity test platform,including the measurement error of digitizers,synchronization acquisition error between channels,data read-write rate and the accuracy of simulation modeling.The test results show that the system can realize the high-speed synchronous acquisition and storage of 96 channels’ data,and complete the test of signal integrity related parameters.The measurements under the load mismatch state of the multi-branch cable networks tested by the signal transmission simulation model are basically consistent with the actual test results,which proves its accuracy.The test platform is docked with the real rocket cable networks and the joint testing of the software and hardware system is completed,which completes the testing of signals and the evaluation of the parameters of different positions.