Simcenter Testing Solutions Time Signal Calculator Tips!

2019-08-29T16:35:54.000-0400
Simcenter Testlab

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Direct YouTube link: https://youtu.be/Qae2IS2rGa8


Using Simcenter Testlab Time Signal Calculator? Here are some tips for you!
User-added image
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.

This article covers:

1. Getting Started with Time Signal Calculator
2. Math Operations: CH1 + CH2
3. Functions Overview
4. Functions List
5. Multiple Channels: CHX
   5.1 CHX and the "Repeat For..." field
   5.2 Using CHX with an Offset
6. Expand CHX into Individual Functions
7. Temporary Storage: VAR

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

1. Getting Started with Time Signal Calculator

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

addin.png

Picture 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.png
Picture 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_list2.png
Picture 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.png
Picture 4: Formula area of Time Signal Calculator
 

When 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.

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.

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To save formula sets and recall them for later, use the buttons. The formula set that is saved can be used from a different project.

2. Math Operations: CH1+CH2

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.png
Picture 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, the Point Identification can be used:

  • 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.png
Picture 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.

For more information on engineering units, see the article: "Simcenter Testlab Units".
 

3. Functions Overview

In addition to math, many other functions 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.png
Picture 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.png
Picture 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.png
Picture 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.

4. Functions List

Popular processing functions include:

5. Multiple Channels: CHX

Sometimes the same operation may need to be performed on multiple channels.

5.1 CHX and the "Repeat For..." field

Take the example of applying a high pass filter to 20 channels at once. 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.png
Picture 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.

5.2 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.png

Picture 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".

6. Expand CHX into Individual Functions

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.png
Picture 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.

7. Temporary Storage: VAR

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.png
Picture 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 Support Center.

Related Links:

Simcenter Testlab Processing Tips

Simcenter Testlab Display tips:

KB Article ID# KB000044204_EN_US

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