LMS Test.Lab: The Versatile "Double X" Cursor
In 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!
More LMS Test.Lab Display Tips: