In Simcenter Testlab (formerly called LMS Test.Lab), the Double X cursor is a wonderful and powerful cursor for data analysis.
Double X: The Basics
To add a Double X cursor to a display, right click and choose “Add Double Cursor -> X” (Hint: Hold down the CTRL key when right clicking on the display to always get the cursor menu)
On the Double Cursor, the left and right cursors can be moved (Picture 2):
Set the cursor to the frequency range desired to perform an analysis.
Double X: Max
Need the maximum over a frequency/rpm range? Want to know the frequency/rpm the max occurs at?
Right click on either the left or right of the Double Cursor and select “Calculations -> Max” (Picture 4).
The maximum appears in cursor legend, along with the frequency at which the maximum value occurs (Picture 5).
Right click on the cursor legend and choose "Copy Values" to paste the maximum value into Excel.
Double X: Frequency Calculator
Looking at some time domain data and wondering what the frequency is present (Picture 6)?
Right click on the Double X cursor and select “Calculations -> Freq (1/deltaT)” as in Picture 7.
Double X: Linear Regression
Trying to figure out your average acceleration from a RPM vs time trace (Picture 8)?
To determine the rate of speed increase (ie, the acceleration) from the RPM vs time, right click on the cursor and choose "Calculations -> Linear Regression" (Picture 9).
The "Linear regression" function fits a line to the data between cursors. The slope and offset of this line are displayed in the legend.
Right click on the legend and choose "Copy Values" to copy/paste the slope and offset to Excel.
Double X: RMS and Color
Want to know the RMS level over a specific frequency range?
Right click on the Double X cursor and choose “Calculations -> RMS” as shown in Picture 11.
Want to highlight the frequency range of interest with a little pizazz? Add a bit of color by right clicking on the Double X cursor and selecting “Properties”.
Turn on “Fill with color:” (Picture 12) and select some beautiful colors (Picture 13)!
Even mix colors with overlapping frequency ranges!
Questions? Email peter.schaldenbrand@siemens.com or contact Siemens PLM GTAC support.
More Simcenter Testlab Display Tips:
Great article! I've noticed sometimes that the double X cursor calculations do not work for large time histories. When that happens the time data icon is half blue and half red, rather than all blue.
This indicates that more data points are available than the option "Max. number of samples used for calculations. To adjust: 1) Go to Tools, Options, Data and increase the number shown for "Max. number of samples used for calculations" by adding one or two zeros to the number. By default, one million data samples are used. When displaying more than one million data samples the icon will be half blue and half red, and the calculations will not be done unless you move the double X cursors to inlcude less than than one million data samples. Press Apply or OK. 2) Refresh the few on the Navigator and the icon should be all blue and your calculations will now work.