Creating Order Plots Using The DATS Rotating Machinery Software

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.

Time series loaded into DATS software
Figure 1: Time series loaded into DATS software

Figure 2 shows the tachometer pulse train in more detail.

Detail of tachometer pulse train
Figure 2: Detail of tachometer pulse train

Next the DATS Rotating Machinery option is used to convert the time series of vibration and tachometer pulses into a waterfall and a speed signal. This process is shown in figures 3, 4 and 5.

Processing steps required to create the waterfall
Figure 3: Processing steps required to create the waterfall
A speed curve generated from the tachometer pulses
Figure 4: A speed curve generated from the tachometer pulses
A waterfall plot with an x axis in frequency (Hz)
Figure 5: A waterfall plot with an x axis in frequency (Hz)

The waterfall can be shown as an intensity plot, as shown in Figure 6.

Waterfall as an intensity plot
Figure 6: Waterfall as an intensity plot

The intensity plot can be shown in dB as seen in Figure 7.

Intensity plot shown in dB
Figure 7: Intensity plot shown in dB

It is possible to show order lines by changing the Graph Settings (Figure 8). Note the show order lines option is ticked.

Settings showing order lines option ticked
Figure 8: Settings showing order lines option ticked

Figure 9 shows the intensity plot scaled in dB with order lines shown.

Intensity plot in dB with order lines shown
Figure 9: Intensity plot in dB with order lines shown

Next we use the Graph Settings again and select the option ‘Show Orders in the X Direction’ as shown in Figure 10.

Settings showing "plot vs orders" option ticked
Figure 10: Settings showing “show orders in x direction” option ticked

The graph in Figure 11 will be shown. This graph displays the waterfall as an intensity plot with the X axis in the order domain.

Intensity plot in dB with order lines shown and plotted against order
Figure 9: Intensity plot in dB with order lines shown and plotted against order
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James Wren

Application Engineer & Sales Manager at Prosig
James Wren is an Application Engineer and the Sales Manager for Prosig Limited. James graduated from Portsmouth University in 2001, with a Masters degree in Electronic Engineering. He is a Chartered Engineer and a registered Eur Ing. He has been involved with motorsport from a very early age with special interest in data acquisition. James is a founder member of the Dalmeny Racing team.

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