Numéro 4 : graphes 3D - waterfall en temps réel et colormaps
m+p Analyzer offers four different types of charts for specific data analysis needs, a 2D single chart, a 2D Multi-chart, a 3D Waterfall chart and a Colormap chart. In this issue we take a look at the 3D chart and its online capabilities.
The 3D chart displays a set of waveforms against a third axis such as time, frequency or RPM. Applicable waveforms include time histories, spectra, FRF, PSD and many more. Just like the 2D charts, the format and properties of the 3D chart can be easily edited and stored as a template, see also Issue 1: Basics of 2D Charts. The following animation shows different styles of the chart: Several spectra are recorded and shown in the waterfall chart during measurement. The user may easily switch between a waterfall and a colormap display by a double click on the chart. In this case we configured the waterfall chart to show a shaded surface, though several other styles are also available.
For the following example we recorded acceleration data of a rotating machine during run-up. We used m+p Analyzer (DSA-Pro license) and an m+p VibPilot acquisition front-end. In addition to the acceleration on the mount we recorded the RPM of the machine. The measurement was configured so that the 14.25 s of time data is automatically split into 57 blocks of 250 ms length. For each block a spectrum is calculated using a FFT algorithm and a Hanning window. The spectra are displayed in a colormap of frequency vs. time. As we also recorded the RPM of the machine, m+p Analyzer will automatically attribute every spectrum with the average RPM during the time of aquisition. Therefore we can easily generate a colormap of RPM vs. frequency, giving a clear indication of the machine’s rotating frequency and its harmonics (i.e. the orders). Exemplarily, a cursor is used to extract the amplitudes of the 1st order over the rotational speed.
This example shows a simple and quick way to analyze a rotating machinery in m+p Analyzer. For more advanced analysis the rotate package may be licensed, which offers advanced tacho acquisition, RPM and time based colormap generation and more sophisticated order tracking features. Contact us for more information about m+p Analyzer and its rotate capabilities.