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Time Signal Calculator Tips!

Siemens Experimenter Siemens Experimenter
Siemens Experimenter

(view in My Videos)
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Using Simcenter Testlab Time Signal Calculator?  Here are some tips for you!

 

The Simcenter Testlab Time Signal Calculator (formerly LMS Test.Lab Time Signal Calculator) is loaded with functions to condition and perform calculations on time files. 

 

Operations include filtering, integration, envelopes, rosette, math, logic operations, and more!

 

Getting Started

To turn it on, choose “Tools -> Add-ins -> Time Signal Calculator” (Picture 1). If using token licensing, this will check out 26 tokens.

 

addin.pngPicture 1: From the main menu, select "Tools -> Add-ins -> Time Signal Calculator"

Go to the “Time Data Selection” workbook and load up some time history data (Picture 2):

  • Click on the button with “…” in the upper right to select time data from either the input basket or the active project
  • Click “Add” or “Replace” to make the time data active

data_select.pngPicture 2: Select the "..." button and select data from Input Basket or Active Project. Push "Add" or "Replace" when done.

 The time data is now available for processing. Each channel is listed under Data Set as shown as Picture 3.

 

data_list.pngPicture 3: Data channels in list ready to process. Each has a Channel Identification assigned (CH#)

Note the following about the time data list:

  • Green color – Indicates data is stored permanently on disk
  • Orange color – Data is available for processing, but not stored permanently
  • “Save As…” – Used to permanently store time data to new file. Your orange data traces should turn green after using this.
  • “Save” button – Used to permanently store time data to existing file. Your orange data traces should turn green after using this.

Formulas can be entered in the Time Signal Calculator to manipulate data in the list (Picture 4).

 

formula_area.pngPicture 4: Formula area of Time Signal CalculatorWhen creating formulas in the Time Signal Calculator, there are some key fields that can be filled out:

  • Id – The destination channel identification for the operation. If left blank will automatically fill in with next available empty channel identification.
  • Formula – The math or function operation to be performed
  • Point Id – The resulting name of the new time history/channel
  • Channelgroup - Choose the group for the resulting data: Acoustic, Vibration, Other, Tacho, or Static.  Both Tacho and Static group data can be used for tracked processing.

 

Math Operations

Once channels are loaded, notice that they are assigned identifications, for example, CH1, CH3, etc.  CH is short for Channel.

 

The math operations ( +, -,   /, * ) can be used with these "CH" identifications (Picture 5). 

 

formula1.pngPicture 5: Data set (upper) and formulas (lower)Examples:

  • CH5+CH6 -  Will add channels 5 and 6
  • 100*CH5 -  Scales channel 5 by 100

When doing these operations, it is not necessary to use the assigned channel identification.  Instead, one can use the Point Identification:

 

  • oilpan+left_head -  Adds channels 5 and 6 which have Point Identifications “oilpan” and “left_head”
  • oilpan+CH6        -  Adds channels 5 and 6

The desired engineering unit can be assigned to the result of any math operation. Use the bracket signs to assign the unit, for example [g]

 

  • (CH5+CH6)[g]

To ensure the data is handled properly, the assigned unit needs to be a valid unit that exists in the Simcenter Testlab Unit system.  If you are not certain what units are valid, go to “Start -> Programs -> Configuration and Unit System…” to get the available list. Note that the units are case-sensitive (Picture 6). 

 

unit_error.pngPicture 6: Warning/error due to specifying uppercase "G" (not in unit set) rather than lowercase "g" (in unit set)

There will be a warning if the unit specified is not available/valid, and the status on the formula will be colored red.

 

F_keys.png

 

 

 

Create additional cells for formula using F key with a yellow star.  There is no limit to the number of formulas.  You can also delete the formulas using the F key with a red X.

 

save.png

 

 

To save formula sets and recall them for later, use the buttons.

 

Advanced Functions

 

In addition to math functions, many other operations can be performed on time data.  To access the other functions, highlight the cell for which to create the functions and press the button with “f(x)” showing on it (Picture 7). 

create_formula.pngPicture 7: Creating a new formula with the "f(x)" button.

A list of functions appears.  The left side of the menu are categories for the functions, while the right side is the list of individual functions as shown in Picture 8.

 

formula_list.pngPicture 8: Time Signal Calculator formula list. Function group on left, individual functions on right.

As an example, to create a high pass filter, select the FILTER_HP function (Picture 9).

 

filter_formula.pngPicture 9: The HP_FILTER formula menu entry.

For a filter function, the following can be filled in:

  • Function1: Enter channel identification or point identification name
  • Freq: Enter cutoff frequency for filter
  • Filtermode: Can be 0 or 1, depending if you direct or zero phase filter is desired
  • Type: IIR or FIR
  • Method: Multiple types of filters
  • Order: Higher this number, sharper the filter

Information about these fields are found in the the knowledge base article: FIR versus IIR Filtering.

 

Press “OK” when finished.

 

To perform the filtering operation, press the “Calculate” button to perform all functions in the list.  “Calculate Selected” can be used to perform only the highlighted function.

 

More Advanced Functions

Other popular processing functions include:

 

Multiple Functions - CHX

Sometimes the same operation may need to be performed on multiple channels.  However, it is not necessary to create 20 separate FILTER_HP functions to filter 20 channels.  This can be done in one step as shown in Picture 10

 

multiple_functions.pngPicture 10: Performing operations on multiple channels with a single formula.

Here is how:

  • Enter the channel number as “CHX” where X is a place holder for the channel number.
  • Enter a range of channel numbers to be used for X into the field called “Repeat for…”.
  • By entering “1:20” in the “Repeat for…” field, channels 1 thru 20 will be filtered in one step.
  • If there are channels without data in the range of 1 to 20, no problem! They will simply be ignored.

Note that the “Repeat for…” field may require using the slider bar in the lower left corner to scroll over to see the field.  It may not be visible by default.

 

Using CHX with an Offset

CHX can be used with an offset on the variable X.  For example, for X equal to 1:

  • CHX would be CH1
  • CHX3 would be CH4

CHX3 means that 3 is added to the current value of X. This could be used to do math between two triaxial accelerometers as shown in Picture 11.

 

CHX_Offset.pngPicture 11: Using CHX and CHX3, the X, Y, and Z directions of two accelerometers are subtracted.

 In the example shown in Picture 11, the X direction of Accel1 will be subtracted from the X direction of Accel2.  The same will be done for the Y and Z directions because of the "Repeat for..." being set to "1:3".

 

Expand CHX to Individual Formulas

After creating a formula using the CHX convention, it can be expanded into individual formula rows using the expand button.

 

expand_button.png

 

 

This can be convenient for naming the results of individual calculations as shown in Picture 12.

 

expand.pngPIcture 12: The expand button can be used to create individual formulas so each result can have a specific Point Id.

When a single formula is used with the CHX convention, the Point Ids are generated automatically.  The user has no control of the names.  The expand button allows individual Point Ids to be entered. 

 

Temporary Data Storage

Sometimes an intermediate calculation is performed enroute to a final calculation.  For example, a high pass filter might be applied to data before integrating as shown in Picture 13.

 

variables.pngPicture 13: Using VAR for the destination id stores data on a temporary basis.

Instead of using a destination id of CH3 to store the high pass filtered data, the destination id is given as VAR3.  This stores the data on a temporary basis.  It will not be permanently stored and take up disk space.

 

The data that is calculated in VAR3 can be referenced by other commands, even though it is not permanently stored.

 

Questions? Email scott.beebe@siemens.com or contact Siemens PLM GTAC support.

 

Related Links:

Simcenter Testlab Processing Tips

Simcenter Testlab Display tips:

Comments
Experimenter
Experimenter

I have a timing signal where the signal was offset incorrectly (by 5 volts) … I went into the Time Signal Calculator hoping there was a way to correct it …. the idea I had was CH1-5.  It appears you can’t just offset (bias) a signal by a value (i.e. CH1-5).

 

Any recommendation on how to get the subtraction to work if I want to use a scalar instead of another channel?  Thoughts?

 

timing1.png

 

Siemens Phenom Siemens Phenom
Siemens Phenom

To do the offset with a scalar quantity, the unit must be defined, and must be the same as unit of the channel.  Try CH1-5[V]

 

timing2.png

 

V is for Voltage in this case.  It is the unit label on the Y-axis of the trace you are trying to offset.

Dreamer
Dreamer

Can I do a calculation on 6 time files at once?  How do I know if it calculated? For example if I was filtering. 

Siemens Valued Contributor Siemens Valued Contributor
Siemens Valued Contributor

You can use the pivot table option to quickly visualize and process multiple measurements from different runs.

 

  • Select your data source ( Choose ‘Active Project’ then ‘Runs:’ All to compare multiple measurements )

 

 

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  • Note when a single calculation is performed data appears as an orange row in the ‘DataSet’ table at top of the page. ( Green = saved & Orange = not saved )

 

 

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  • Using the ‘DataSet’ drop down menu at the top of the page select ‘Channels pivot’

 

 

pic_3.png

 

pic_4.png

 

  • Additionally, you can used the two drop down boxes to select from 10 different data attributes for sorting and selecting data for processing or visualization.

pic_5.png

 

 

  • Calculations in Time Signal Calculator are always done on all runs. Using the ‘Channels pivot’ option lets you verify that the calculations done on all runs.

 

 

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  • Save all the processed data to the active section of your project by press the ‘Save As..’ button. ( Note: The calculated data will be green after it saved).

 

 

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