In this tutorial we will be creating order plots using waterfall and intensity displays using use the DATS.toolbox and Rotating Machinery Analysis option.
To begin, a noise, vibration or other signal of interest should be captured along with a tachometer signal.
In Figure 1 we have loaded a time series (in this case an acceleration signal) and a time series of a tachometer pulse train into the DATS software.
Continue reading Creating Order Plots Using The DATS Rotating Machinery Software
James WrenAdd a Comment3543class="post-3543 post type-post status-publish format-standard hentry category-dats category-signal-processing category-tutorial tag-block-size tag-blocksize tag-fft tag-fft-block-size tag-frequency-domain tag-frequency-spacing tag-waterfall tag-waterfall-frequency-spacing tag-waterfall-plot"Let us try to understand what waterfall frequency spacing is. Waterfall frequency spacing is the gap between spectral lines in an FFT plot.
For example, if you had an analysis frequency of 0Hz to 100Hz and 100 spectral lines, then Frequency Spacing is 1Hz.
So why is there a ‘Requested Frequency Spacing’ and an ‘Actual Frequency Spacing’? Continue reading What is waterfall frequency spacing? And how does the DATS parameter ‘Requested Frequency Spacing’ work?
James WrenAdd a Comment3539class="post-3539 post type-post status-publish format-standard hentry category-signal-processing category-tutorial tag-block-size tag-blocksize tag-fft tag-fft-block-size tag-frequency tag-frequency-domain tag-frequency-resolution tag-order-plot tag-rpm tag-waterfall tag-waterfall-plot tag-waterfall-smearing"When analysing a waterfall or performing order analysis it is important to consider the frequency resolution or the frequency spacing.
There is often a desire to increase the resolution to finer and finer detail. But that is a process of diminishing returns, and actually fraught with danger. And that danger is waterfall smearing. Continue reading What is “waterfall smearing”?
James WrenAdd a Comment2763class="post-2763 post type-post status-publish format-standard hentry category-dats category-tutorial tag-accelerometer tag-accelerometers tag-dats tag-example-worksheet tag-resultant tag-time-histories tag-time-history tag-triaxial tag-waterfall tag-waterfalls"A user has three signals captured using a triaxial accelerometer and asked “What is the simplest way to get the XYZ resultant from run-up file?” He had tried forming a resultant of the raw time histories, but didn’t fully understand the resultant time history.
Of course, the correct way of processing the data is to calculate the individual waterfalls from the x, y & z data and then calculate a resultant waterfall. Continue reading How Do I Get An XYZ Resultant Waterfall
Dr Mike DoneganAdd a Comment2919class="post-2919 post type-post status-publish format-video hentry category-dats category-tutorial category-video tag-order-plot tag-order-trace tag-orders tag-tacho-signal tag-time-history tag-video tag-waterfall tag-waterfall-plots tag-youtube post_format-post-format-video"A step-by-step introduction to creating order and waterfall plots from a time history and a tacho signal.
James WrenAdd a Comment2817class="post-2817 post type-post status-publish format-standard hentry category-dats category-tutorial tag-articulation tag-articulation-index tag-harshness tag-metrics tag-noise-vibration tag-sound-quality tag-sound-quality-metrics tag-waterfall"Use the following sequence to get the Articulation Index (AI) vs rotational speed:
In this case select either $AI_ANSI or $AI_VEH.
These are different calculations with
AI_ANSI is calculated in the range 0 to 1
AI_VEH is calculated as percentage in range 0 to 100
Dr Mike DoneganAdd a Comment2660class="post-2660 post type-post status-publish format-video hentry category-dats category-tutorial category-video tag-3d tag-dats tag-db tag-linear tag-logarithmic tag-tutorial tag-video tag-waterfall post_format-post-format-video"James Wren explains how to view 3-D visualizations using linear, logarithmic & dB scales.
James WrenAdd a Comment2639class="post-2639 post type-post status-publish format-video hentry category-dats category-signal-processing category-tutorial category-video tag-dats tag-fft tag-harmonics tag-noise tag-orders tag-rotating-machinery tag-speed tag-tacho tag-vibration tag-video tag-waterfall post_format-post-format-video"This is complete version of the video illustrating my recent article How To Measure Noise & Vibration In Rotating Machines. This video was previously published on the blog in 3 parts.
The video will be best enjoyed by selecting the 720p option and selecting full screen mode.
Chris MasonAdd a Comment
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