National Instruments Order Analysis Toolset manuale d’uso

LabVIEW TM Order Analysis Toolset User Manual LabVIEW Order Analysis T oolset User Manual August 2003 Edi tion Part Number 3228 79B-01[...]

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© National Instruments Corporation v LabV IEW Order Analysis Toolset User Manual Contents About This Manual How to Use This Manual .............. ............ .............. ........... .............. .............. ............ .... vii Conventions ............ .............. ........... .............. ............ .............. .............. .[...]

Contents LabVIEW Order Analysis Toolset User Manual vi ni.com Chapter 3 Gabor Transform-Based Order Tracking Overview of Gabor Order Analysis ................. .............. .............. .............. ........... ......... 3-1 Extracting the Order Components ............. .............. .............. ........... ............... .............. [...]

© National Instruments Corporation vii La bVIEW Order Analysis Toolset User Manual About This Manual This manual provides information about the LabVIEW Order Analysis T oolset, including system req uirem ents, inst allation, and suggestions for getting started with order analysis and the toolset. The manual also provides a brief discussion of the [...]

About This Manual LabVIEW Order Ana lysis Tool set User Manual viii ni.com bold Bold text denotes items that you must select or click in the software, such as menu items and di alog box options. Bo ld text also denotes the name s of parameters, dialog boxes, sections of dialog box es, windo ws, menus, palettes, and front panel controls and buttons.[...]

© National Instruments Corporation 1-1 La bVIEW Order Analysis T oolset User Manual 1 Introduction to the LabVIEW Order Analysis T oolset This chapter introduces the LabVIE W Order Analysis Toolset and the Order Analysis Start- Up Kit, outli nes system requirements, and gi ves installation instruct ions. Over view of the LabVIEW Order Analysis T o[...]

Chapter 1 Introduction to the LabVIEW Order Analysis T oolset LabVIEW Order Analysis T oolset User Manual 1-2 ni.com application is built with componen ts found in the LabVIEW Order Analysis Toolset. The order analysis application provid es an ex ample of ho w the LabVIEW Order Analysis T oolset can help yo u successfully complete analysis projects[...]

Chapter 1 Intr oduction to the LabVIEW Order Analysis T oolset © National Instruments Corporation 1-3 La bVIEW Order Analysis T oolset User Manual System Requirements You must have LabVIEW 6.1 or later Full Development System or Professional Development System installed to ru n the LabVIEW Order Analysis Toolset. Note Refer to the LabVIEW Release [...]

Chapter 1 Introduction to the LabVIEW Order Analysis T oolset LabVIEW Order Analysis T oolset User Manual 1-4 ni.com Example VIs If you have experience with order an alysis, the example VIs, located in the examplesOrder Analysis direct ory, can help you l earn how to us e the LabVIEW Order Analysis Toolset. The example VIs illustrate the following[...]

Chapter 1 Intr oduction to the LabVIEW Order Analysis T oolset © National Instruments Corporation 1-5 La bVIEW Order Analysis T oolset User Manual set to DAQ and you click the Run button on the front panel of the example VI, one of the following VIs opens: • Acquire Data (Analog T ach) VI • Acquire Data with PXI 4472 and TIO VI Refer to the Ac[...]

Chapter 1 Introduction to the LabVIEW Order Analysis T oolset LabVIEW Order Analysis T oolset User Manual 1-6 ni.com tachometer signal and S&V for the sound or vibration sensor. After choosing data acquisition settings, enter the number of pulses yo u want the tachometer to generate per revolutio n in the Tach Pulse/Rev text box. Use the contro[...]

Chapter 1 Intr oduction to the LabVIEW Order Analysis T oolset © National Instruments Corporation 1-7 La bVIEW Order Analysis T oolset User Manual Figure 1-3. Acquire Data with PXI 4472 a nd TIO VI Conf iguration T ab Use the Configuration tab of the A cquire Data with PX I 4472 and TIO VI, shown in Figure 1-3, to configure the DAQ devices. Use on[...]

Chapter 1 Introduction to the LabVIEW Order Analysis T oolset LabVIEW Order Analysis T oolset User Manual 1-8 ni.com Figure 1-4. Acquire Data with PXI 4472 and TIO VI Acquisition T ab The Acquisition tab, shown in Figure 1-4, allows you to acquire and observe data. Click the Acquire button to acquire data. Co ntinue to configure the data acquisitio[...]

© National Instruments Corporation 2-1 La bVIEW Order Analysis T oolset User Manual 2 Order Analysis This chapter gives brief descriptions of the need for order analysis, the basic concepts of order analysis, the effect of rotational speed on order identification, and the di ffere nt order analysis methods. Order Analysis Definition and Applicatio[...]

Chapter 2 O rder Analysis LabVIEW Order Analysis T oolset User Manual 2-2 ni.com vibration signals. The frequency-domain representations of noise and vibration behave as harmonics of the machine rotational speed. In many industries, the harmonics related to the rotati onal speed are referred to as orders. The correspond ing harmonic analysis is cal[...]

Chapter 2 O rder Analysis © National Instruments Corporation 2-3 La bVIEW Order Analysis T oolset User Manual Assuming that speed remains con stant during data acquisition, you can use the following equations to switch between the frequency domain and the order domain. Orders often reflect the physical characteristics of rotating machines. As in c[...]

Chapter 2 O rder Analysis LabVIEW Order Analysis T oolset User Manual 2-4 ni.com Like classical harmonic an alysis, order analysis is a powerful tool for gaining a better understanding of the condit ion of rotating machinery . Ho wev er , compared to ha rmonic analysis, order analysis is more ef fecti v e for the analysis of rotating machiner y bec[...]

Chapter 2 O rder Analysis © National Instruments Corporation 2-5 La bVIEW Order Analysis T oolset User Manual Figure 2-3. PC Fan Running at Constant Speed The bottom plot in Fig ure 2-3 depicts th e tachometer pulses and the signal from an accelerometer mounted on the PC fan. The plot on the left in Figure 2-3 illustrates a con ventional po wer sp[...]

Chapter 2 O rder Analysis LabVIEW Order Analysis T oolset User Manual 2-6 ni.com V ariable Rotational Speed In addition to testing rotating machinery ru nning at a constant speed, researchers often perform tests involving ru n-up and run-down. Like a swept-sine stimulus, testing run-u p and run-down provides a stimulus over a wide range of frequenc[...]

Chapter 2 O rder Analysis © National Instruments Corporation 2-7 La bVIEW Order Analysis T oolset User Manual time, the ov erall frequency bandwidth, as measured from the con v entional power spectrum, is the minimum. Figure 2-5 depicts a signal whose frequency changes as a function of time. Figure 2-5. Frequency Changes Over Time Although the sig[...]

Chapter 2 O rder Analysis LabVIEW Order Analysis T oolset User Manual 2-8 ni.com harmonics ov erlap in the con ventional po wer spectrum, you are unable to identify different harmonics by using the con v entional po wer spectrum. Figure 2-6 sho ws the signal from the sa me PC fan as the one depicted in Figure 2-3. Howe ver , in Fi gure 2-6, the rot[...]

Chapter 2 O rder Analysis © National Instruments Corporation 2-9 La bVIEW Order Analysis T oolset User Manual orders overlap, you are unable to de riv e meaningful in formation about the individual orders. Harmonic Analysis Harmonic analysis is suitable for th e analysis of rota ting machiner y only when the rotational speed remains const a nt. In[...]

Chapter 2 O rder Analysis LabVIEW Order Analysis T oolset User Manual 2-10 ni.com Currently , the following methods generally are used to perform ord er analysis: • Gabor transform • Resampling • Adapti ve f ilter The LabVIEW Order Analysis T oolset provides the Gabor-transform-based method and the resampling metho d of order analysis. Gabor [...]

Chapter 2 O rder Analysis © National Instruments Corporation 2-11 Lab VIEW Order Analysis T oolset User Manual Figure 2-7. Padding Schemes In zero padding, shown in Figure 2-7(a), the first window and the last windo w only cov er one data block each. The remaining area in the range of the window is f illed with zeros. Thus, extra data samples are [...]

Chapter 2 O rder Analysis LabVIEW Order Analysis T oolset User Manual 2-12 ni.com Figure 2-8 shows two e xamples of padding. Figure 2-8. Padding Examples Refer to Appendix A, Gabor Exp ansion and Gabor Transf orm , for more information about the Gabor tr ansform and the Gabor expansion. Refer to Chapter 3, Gabor Transform-Based Order Tracking , for[...]

Chapter 2 O rder Analysis © National Instruments Corporation 2-13 Lab VIEW Order Analysis T oolset User Manual Resampling Resampling is a widely used method of order analysis. Figure 2-9 illustrates the resamp ling method. Figure 2-9. Resampling In the resampling met hod, time-samples are con verted to angle samples. The time-samples are samples o[...]

Chapter 2 O rder Analysis LabVIEW Order Analysis T oolset User Manual 2-14 ni.com After acquiring angle samples with either hardware or software, you can perform a Fourier transform on the angl e samples to analyze them. Because the time domain has changed into the angl e domain, the frequency domain now becomes the order domain. Y ou can separate [...]

Chapter 2 O rder Analysis © National Instruments Corporation 2-15 Lab VIEW Order Analysis T oolset User Manual After the resampling process takes place, reco vering a time wa ve form at a specific order might be dif ficult. Refer to Chapter 4, Resampling-Based Order Analysis , for information about how the LabVIEW Order Analysis T oolset uses soft[...]

© National Instruments Corporation 3-1 La bVIEW Order Analysis T oolset User Manual 3 Gabor T ransform-Based Order T racking This chapter discusses a new order analysis method based on the Gabor transform and provided by the LabV IEW Order Analysis Toolset that enables you to complete the foll owing tasks: • Analyze the order components of a noi[...]

Chapter 3 G abor T ransform-Bas ed Order T racking LabVIEW Order Analysis T oolset User Manual 3-2 ni.com In Figure 3-1, the m agnitudes of co ef fici ents are sho wn as gray scale, with full white indicating a maxim al magnitude and full black indi cating a minimal magnitude. Because the rotational speed changes little in each time portion of the [...]

Chapter 3 Ga bor T rans form-Based Order T racking © National Instruments Corporation 3-3 La bVIEW Order Analysis T oolset User Manual Complete the following steps to perform Gabor order analysis. 1. Acquire data samples from the tachometer and noise or vibrat ion sensors synchronously at som e constant sample rat e. 2. Use the LabVIEW Order Analy[...]

Chapter 3 G abor T ransform-Bas ed Order T racking LabVIEW Order Analysis T oolset User Manual 3-4 ni.com processed b y a Gabor tran sform, the index of the n th order is given b y the following equation. , where RPM is the av eraged instantaneous rotational speed in the time interval, N is the number of frequency bins, and f s is the sampling freq[...]

Chapter 3 Ga bor T rans form-Based Order T racking © National Instruments Corporation 3-5 La bVIEW Order Analysis T oolset User Manual Figure 3-3(b) illustrates const ant orde r bandwidth. The nei ghborhood is considered as the region between and . While the frequency bandwidth varies in time, the order bandwidth k remains constant. Y ou can use t[...]

Chapter 3 G abor T ransform-Bas ed Order T racking LabVIEW Order Analysis T oolset User Manual 3-6 ni.com VI to perform the mask oper ation. Refer to the LabVIEW Or der Analysis Toolset Help for informatio n about the T emplate to Mask VI. Y ou can consider the mask operation a time-v ariant bandpas s f ilter in the joint time-frequency domain. The[...]

Chapter 3 Ga bor T rans form-Based Order T racking © National Instruments Corporation 3-7 La bVIEW Order Analysis T oolset User Manual Figure 3-4(b) shows a mask array around t he fourth order with a constant frequency bandwidth. The TR UE v alues comprise the white area, while the F ALSE values comprise the black areas. Figure 3-4(c) sho ws the m[...]

Chapter 3 G abor T ransform-Bas ed Order T racking LabVIEW Order Analysis T oolset User Manual 3-8 ni.com time-variant f ilters. Figure 3-6 shows an original signal and the spectrum of the reconstructed signal. Figure 3-6. Spectrum of Reconstructed Signal In Figure 3-6, on e row is selected from the joint time-frequency coef f icient array . The se[...]

Chapter 3 Ga bor T rans form-Based Order T racking © National Instruments Corporation 3-9 La bVIEW Order Analysis T oolset User Manual Figure 3-7. 2D Spec tral Maps Figure 3-7(a) is the frequ ency-time spectral map generated directly from the Gabor coeff icients. The magnitudes of coef f icients are sho wn as gray scale, with full white indicating[...]

Chapter 3 G abor T ransform-Bas ed Order T racking LabVIEW Order Analysis T oolset User Manual 3-10 ni.com Figure 3-7(c) shows the frequency-rpm spectral map. The horizontal axis represents rpm, or rotational speed. Y ou can map the rpm axi s from the time axis in the frequency-time spectral map by the rpm-time function. The frequency of each order[...]

© National Instruments Corporation 4-1 La bVIEW Order Analysis T oolset User Manual 4 Resampling-Based Order Analysis This chapter describes the resampl ing method provided by the LabVIEW Order Analysis T oolset, determin ing the time instance for resamplin g, resampling vibration data, and slow roll compensation. LabVIEW Order Analysis T oolset R[...]

Chapter 4 R esampling-B ased Order Analysis LabVIEW Order Analysis T oolset User Manual 4-2 ni.com Complete the following steps to perform resampling-based order analysis. 1. Acquire data samples from tachometer and noise or vibration sensors synchronously at some constant sample rat e. 2. Use the LabVIEW Order Analysis T oolset VIs to complete the[...]

Chapter 4 Resampling-B ased Order Analysis © National Instruments Corporation 4-3 La bVIEW Order Analysis T oolset User Manual a larg er marg in of samples for anal ysis and need to resamp le 2.5 K samples in one rev olution. Most of the time, a tachometer does not produce enough p ulses in one rev olution. Therefore, you need to multiply the numb[...]

Chapter 4 R esampling-B ased Order Analysis LabVIEW Order Analysis T oolset User Manual 4-4 ni.com Figure 4-2. Original T ime Sequence and CI C Interpolation Filter with an Interpolation Factor of Eight Resampling Vibration Data The resampling operation converts a vibrati on signal from the time domain into the angle domain. To resample vi bration [...]

Chapter 4 Resampling-B ased Order Analysis © National Instruments Corporation 4-5 La bVIEW Order Analysis T oolset User Manual According to the Nyquist sampling theo rem, you can exactly reconstruct the time signal x ( t ) from samples x ( nT s ) with the following equation. (4-1) where h s is a sinc function defined b y . Figure 4-3 shows the plo[...]

Chapter 4 R esampling-B ased Order Analysis LabVIEW Order Analysis T oolset User Manual 4-6 ni.com When monitoring shaft vibration wi th a proxi mity probe, the acquire d signal contains not only the vibrati on of the shaft but also the shaft runout, such as a nonconcentric shaft condition at the probe measuremen t plane. Y ou can measure the shaft[...]

© National Instruments Corporation 5-1 La bVIEW Order Analysis T oolset User Manual 5 Calculating Rotational Speed This chapter describes the digital differentiator method used by the LabVIEW Order Analysis Toolset to calculate rotational speed and describes averaging pulses to smooth noisy calcu lated rotational speed results. Digital Differentia[...]

Chapter 5 Ca lculating Rotational Speed LabVIEW Order Analysis T oolset User Manual 5-2 ni.com Figure 5-1. T achometer Signal and Rotation Angle The arriv al time t k of the pulses P ( k ) in the tachometer signal correspond to the cumulativ e rotation angle θ ( t k ). The cumul ativ e rotation angle function θ ( t ) increases by a fi xed angle ?[...]

Chapter 5 C alculating Rotational Speed © National Instruments Corporation 5-3 La bVIEW Order Analysis T oolset User Manual of an equally spaced sequence re quires fewer computations than calculating the first deri vati ve of an unequally spaced sequence. For the e venly separated func tion series t k , you can use a digital differentiator to calc[...]

Chapter 5 Ca lculating Rotational Speed LabVIEW Order Analysis T oolset User Manual 5-4 ni.com Figure 5-2 sho ws an example of the rotational speed calculated from the tachometer pulses. Figure 5-2. Cumulative Revolution and Rotational Speed In Figure 5-2, the dotted line repres ents the results of calculating the rotational speed with no av eragin[...]

© National Instruments Corporation A-1 LabVIEW Order Analysis T oolset User Manual A Gabor Expansion and Gabor T ransform This appendix presents an o vervie w of the Gabor expansion and the Gabor transform methods u sed in the LabVIEW O rder Analysis T oolset. This appendix also describes appl ication issues associated with using the discrete Gabo[...]

Appendix A Gabor Expansion and Gabor T ransform LabVIEW Order Analysis T oolset User Manual A-2 ni.com The sampled STFT is also known as th e Gabor transform and is represented by the follo wing equation. (A-2) where ∆ M represents the time sam pling interval and N represents the total number of frequency bins. The ratio between N and ∆ M deter[...]

Appendix A Gabor Expans ion and Gabor T ransform © National Instruments Corporation A-3 LabVIEW Order Analysis T oolset User Manual corresponding dual window function from ∆ M independent li near systems with the following equation. (A-4) where L denotes the window length. denotes a periodic auxiliary function 1 given b y the following equation.[...]

Appendix A Gabor Expansion and Gabor T ransform LabVIEW Order Analysis T oolset User Manual A-4 ni.com Discrete Gabor -Expansion-Based T ime-V arying Filter Initially , discr ete Gabor expansion seems to provide a feasible method for con verting an arbitrary signal from the time domain into the join t time-frequency domain or vice versa. Ho we ver [...]

Appendix A Gabor Expans ion and Gabor T ransform © National Instruments Corporation A-5 LabVIEW Order Analysis T oolset User Manual 4. Compute the new Gabor coef f icients after you obtain the time wav eform. 5. Repeat steps 1 through 4 until the time waveforms con verge. W ithout a loss of generality , rewrite the Gabor expansion from Equation A-[...]

Appendix A Gabor Expansion and Gabor T ransform LabVIEW Order Analysis T oolset User Manual A-6 ni.com C k and con verge. with . For with , the support of C k in the time-fr equency domain is inside the masked area if and only if the following equation is true. (A-6) for 0 ≤ k < N and 0 ≤ m < . T wo trivial cases for Equation A-6 are crit[...]

© National Instruments Corporation B-1 LabVIEW Order Analysis T oolset User Manual B References This appendix lists the reference material used for the LabVIEW Order Analysis T oolset. • Albright, Michael, and Shie Qian. Comparison of the New Proposed Gabor Order Tracking Technique vs. Other Order Tracking Meth ods . SAE Noise and V ibration Con[...]

© National Instruments Corporation C-1 LabVIEW Order Analysis T oolset User Manual C T echnical Support and Professional Ser vices Visit the following sections of the National Instruments Web site at ni.com for technical support an d professional services: • Support —Online technical support resources include the following: – Self-Help Resou[...]

© National Instruments Corporation G-1 LabVIEW Order Analysis T oolset User Manual Glossar y Numbers/Symbols Infinity . 2D T wo-dimensional. A adapti ve filter A type of filter that operates on a recursi ve algorithm to achie ve the goal of optimum. It is self-desig ning and suitable for tr acking time variations of the input signal, but complete [...]

Glossary LabVIEW Order Analysis T oolset User Manual G-2 ni.com F FFT Fast F ourier transform. fundamental component Portion of a signal whose frequency is at the fundamental frequency . G Gabor coef ficient The resu lt of Gabor transform. Gabor e xpansio n The in verse Gabor transform us ed on Gabor coef f icients to recov er a time domain input s[...]

Glossary © National Instruments Corporation G-3 LabVIEW Order Analysis T oolset User Manual order curves The high power density curv es in a spectral map which indicate order components. orthogonal-like Gabor transform pair The pair is composed of a Gabor transform and a Gabor expansion when the Gabor coeff icients c m , n found by each method are[...]

© National Instruments Corporation I-1 La bVIEW Order Analysis T oolset User Manual Index A adaptive filter, 2-15 analysis of rotating machinery, using the toolset, 1-2 applying an iteration to reconstruct a time waveform, A-4 C calculating rotational speed, 5-1 averaging pulses, 5-3 digital di fferentiat or, 5-1 calculating wavefo rm magnitud e, [...]

Index LabVIEW Order Analysis T oolset User Manual I-2 ni.com K KnowledgeBase, C-1 M masking, 3-5 extracting orders, 3-6 reconstructing a signal, 3-7 N National Instruments customer education, C-1 professional services, C-1 system integration services, C-1 technical support, C-1 worldwide offices, C-1 O online technical support, C-1 order analysis a[...]