Research On Digital Monitoring And Diagnosing System Of Shafting Torsional Vibration With Labwindows/CVI Software

Torsional vibration of reciprocating machine’s shafting is one of the main reasons whichfrequently results in the breaking off of the shafting. Therefore signal of torsional vibrationhas been paid more and more attentions in the domain of reciprocating machine’s failurediagnosis. Application of virtual instrument technology is compulsory for the development oftorsional vibration’s measuring in order to meet the need of high measuring precision, widemeasuring range, stable and credible performance, easy operation, channels measuringsynchronously and results exporting quickly, which could be propitious to avoid the grievousaccidents caused by torsional vibration.In this dissertation, a digital torsional vibration recording and diagnosing system isdesigned to predict a machine failure. Combining the analyzing with measuring, thedeveloped system achieves some functions, such as continuous recording, analyzing anddiagnosing for the torsional vibration. The hardware of the system is composed by a digitalcollection board named USB6211made by USA NI Company and an independent developedmodulating circuit board. The software is developed by the platform of Labwindows/CVI.The system has some functions as the following. It has a two-channel torsional vibrationsignals measuring synchronously, raising and discussing a method for advancing thetime-frequency transform precision which could carry through FFT for the torsional vibrationsignal even needs higher precision. In addition, the important test data can be extracted just asspectrum amplitude expediently during the spectrum analysis which does not need to do it artificially. Spectrum and waterfall graphs can also be plotted easily and the comparisonanalysis of two-channel signals can be carried out. Free torsional vibration calculation and theadditional torsional stress calculation function are also included in the system. The monitormodule of the system can be used to monitor the rotation speed, angle amplitude and otherrelevant characteristic parameters online and becomes a “Black Box” during the alarmingsituation. The system also contains the save and repeat function of the data, table printfunction. Detailed help information are also included.The system has been successfully applied to several real time tests of machines and theresults are compared with the LMS. It is showed that the results from this system is accuracyand reliable. The running of the system is fast and it can be easily used which would definitely offer some technological support and reference for the torsional vibration test andresearch.