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)

Picture 1: Right click in display (press CTRL if needed) and "Add Double Cursor -> X"

On the Double Cursor, the left and right cursors can be moved (Picture 2):

Left Cursor: Moves both cursors together at the same time. The cursors stay fixed distance apart

Right Cursor: Moves only the right cursor, changes the distance between the two cursors

Picture 2: Left cursor moves both cursors, right cursor changes width

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?

Picture 3: Using the Double X cursor to find the maximum value in a frequency range

Right click on either the left or right of the Double Cursor and select Calculations -> Max (Picture 4).

Picture 4: Right click on the double cursor and choose "Calculations -> Max". Maximum will be displayed in a cursor legend.

The maximum appears in cursor legend, along with the frequency at which the maximum value occurs (Picture 5).

Picture 5: The maximum value and it's corresponding frequency will be shown in the legend.

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)?

Picture 6: Damped sine wave time history.

Right click on the Double X cursor and select Calculations -> Freq (1/deltaT) as in Picture 7.

Picture 7: Determine the frequency of time data by selecting "Calculations -> Freq(1/T)"

Double X: Linear Regression

Trying to figure out your average acceleration from a RPM vs time trace (Picture 8)?

Picture 8: RPM vs time data trace

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).

Picture 9: To determine the rate of acceleration, right click and choose "Calculations -> Linear regression"

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?

PIcture 10: Determining the RMS value of a frequency band within a spectrum

Right click on the Double X cursor and choose Calculations -> RMS as shown in Picture 11.

Picture 11: Right click on the Double X cursor and choose "Calculations -> RMS"

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 .

Picture 12: Select a color for the Double X cursor

Turn on Fill with color: (Picture 12) and select some beautiful colors (Picture 13)!

Picture 13: Double X cursor with filled color

Even mix colors with overlapping frequency ranges!

Picture 14: Overlapping colors in dual Double X cursors