Simcenter Testlab Neo Process Designer allows users to chain multiple methods together to create custom processes for analyzing data. “Variables” can be defined prior to running a process to set processing parameters or data attributes to be used throughout the process.
An example of variables being used to define the orders and frequency resolution for a process are shown in Figure 1 below:
Figure 1: Process variables are defined in the ribbon before running a process. In this case the frequency resolution and orders were defined in advance.
Process Variables in Simcenter Testlab Neo can be used to set method parameters, define variables for calculations, or set data attributes. Variables can be defined globally, or on the channel or run level.
Variables were introduced with Simcenter Testlab Neo 2406. With Simcenter Testlab 2506 and higher, conditional variables were added as well as the ability to initialize variables from an Excel file.
This article covers both standard and conditional variables and how to use them in Simcenter Testlab Neo Process Designer: 1. Defining a Variable 2. Method Parameters 3. Factors in Calculations 4. Data Attributes and Conditional Variables 5. Variables and Excel
1. Defining a Variable
To define variables, make sure “Expert Mode” is enabled by clicking on the check box in the ribbon. Then click on the “Process Variables” icon in the Process ribbon of Simcenter Testlab Neo Process Designer. (Figure 2).
Figure 2: To use variable in a process, turn on “Expert Mode” (via checkbox) and click on the “Process Variables” icon in the Process Ribbon of Simcenter Testlab Neo Process Designer.
Variables to be used in the process can be defined in the ‘Process Variables” menu shown in Figure 3.
Figure 3: Variables names and values are be entered in a table in the “Process Variables” menu.
The “Process Variables” menu:
Add or delete lines for defining variables using the icons in the upper left corner.
Enter names and values for variables.
Can import variables from Excel using the appropriate icon.
Allows user to define conditions for the variables.
Variables need to be defined before running a process.
To use variables in the methods, see the examples in the next sections.
More about Simcenter Testlab Neo Process Designer:
Variables can be used to set calculation parameters used in methods.
In the process below (Figure 4) there are four different map methods (spectral map, octave map, tonality map, and prominence ratio map).
Figure 4: Using variables the rpms range of four different map methods can be set in one place.
Each map method can be tracked on a function like rotational speed (RPM). Rather than doing this for each method separately, variables for lower RPM, upper RPM, and increment can be defined once using variables and applied to all map methods (Figure 5).
Figure 5: Three variables defined for the upper rpm, lower rpm, and rpm increment to be used in the map methods.
Double click on one of the map methods to change the properties.
In the map method menu, hover the mouse next to the parameter field to be changed from manual entry to a variable. A “(x)” icon will appear next to the parameter field (Figure 6):
Figure 6: Switch parameter fields in the method from free text entry to variable mode by clicking on the (x) icon next to the parameter field. Hover the mouse to make the icon appear.
Click on the "(x)" icon to switch to variable mode. The field will change from a free text entry field to a fixed field.
To assign a variable to the field, click on the down arrow next to the field and select one of the variables that were defined in the “Process Variables” menu (Figure 7):
Figure 7: After activating the variable mode for the parameter field, click on the arrow to choose which variable to assign.
With the variable assigned, now the parameter is set by the values entered under the “Process Variables” menu.
3. Factors in Calculations
Variables can be used to define factors that are used in calculations. In the process below, a variable is used to enter the wheel diameter to convert wheel rpm into vehicle speed to be used with the “Calculate” method in the process (Figure 8):
Figure 8: A variable called “Wheel_diameter_meters” is used in the “Calculate” method convert measured wheel rpm to vehicle speed.
Formulas used in the “Calculate” method utilize the engineering units to get the correct result. In this case, the square bracket symbols are used to assign the variable a unit in the “Process variables” menu.
In Simcenter Testlab 2506, variables are not supported directly in the “Calculate” method. The “Pass” and “Define Value” methods allow the variable to be used in the “Calculate” method.
First the “Pass” method is used to select the just the “wheel_rpm” channel to be used with the “wheel_diameter_meters” variable as shown Figure 9.
Figure 9: The “Pass” method is used to select just the “wheel_rpm” channel.
In the “Define value” method, under “Methods”, set the “Name” and “Value” field. The "Value" field will be switched to the variable as shown in Figure 10.
Figure 10: Use the “wheel_diameter_meters” variable in the “Define Value” method.
The “Value” is the variable defined in the “Process Variables” menu. The “Name” will be used in the “Calculate” method.
The formula to convert wheel RPM to vehicle speed is entered in the “Formula set” of the “Calculate” method as shown in Figure 11:
Figure 11: Enter the formula to convert wheel RPM to vehicle speed.
In the formula set enter:
Turn on “Calculated Statistics”.
Select “Wheel Diameter” (entered in the “Define Value” method) under the “Calculated statistics” column.
R1 and R2 refer to the variable and measured wheel rpm channel respectively.
In V1, enter the formula. Under “Point” enter the name for the calculated channel.
“Y-axis quantity” and “Unit” set the desired engineering unit (in this case “Speed” and “km/h”) of the calculated channel.
Run the process (click on “Run” button in lower left) to convert the wheel RPM to vehicle speed as shown in Figure 12.
Figure 12: After running the process, the wheel rpm (green, bottom) is converted to vehicle speed (red, top).
When a new vehicle is measured, the wheel diameter can be easily updated in the “Process Variables” rather than having to find it in the Calculate method.
4. Data Attributes and Conditional Variables
Variables are not only numbers, but they can also be text strings.
Variables can also be “Conditional”. Instead of a single value for the variable (e.g., a “simple” variable), the value can change depending on a condition.
For example, conditional variables can be used to add different “User Comments” to individual channels of data. An example process is shown in Figure 13.
Figure 13: Process to add a User Comment to data using conditional variables.
To create a conditional variable, define the same variable multiple times in the “Process Variables” table as shown in Figure 14:
Figure 14: Define the same variable name multiple times to create a “conditional” variable. In this case, the variable "User_Comment" has three possible values.
To create a “conditional” variable:
The same “Name” must be used multiple times.
Based on either “Channel”, “DOF ID”, or “Run name” there is a different designated value for the variable. Something other than “*” needs to be entered in the columns.
Conditional variables have different icons than simple variables.
In this example, the “User_Comment” variable is more descriptive and understandable (e.g., “Differential_ForeAft_Direction” rather than “Differential:-X”. It will be used when plotting the data rather than the original channel name.
In this process, the value in the “User_Comment” variable is added to the time history data placed in the “Input Basket”. When creating new time histories, it is a good practice to choose “Do not save” in “Input” method properties as shown in Figure 15.
Figure 15: Setting the “Input Data” to “Do not save” in the “Input” method prevents duplicating the time history data.
By selecting “Do no save”, duplication of the time data in the result is avoided. With the default settings “Save time data as link” the original time histories and the modified time histories would both be in the resulting run.
In the “Metadata Editing” method properties, hovering just to the right side of the “User channel ID 1” field will allow the field to be set to a variable once the icon appears (Figure 16):
Figure 16: In the “Metadata editing” method, hover to the right of the “User channel ID 1” field, switch the parameter to a variable, and then use the down arrow to select the variable.
Once the field is switched to a variable field, use the down arrow to select the variable to use.
After running the process, the “User Channel Id” can be shown in the display legend. Right click on the legend and select “Options…” as shown in Figure 17.
Figure 17: Right click on the display legend to show the “User Channel Id” field in the display.
In the “Custom Content” tab, find the “User channel ID 1” field and move it from the left side to the right side. Press Ok to see it in the display.
5. Variables and Excel
Instead of typing all the variables to use in the “Process Variables” menu, they can be read from an Excel file.
To set the variables using Excel, click on the Excel icon (last icon in the Process Variables menu) as shown in Figure 18:
Figure 18: Click on the Excel icon in the “Process Variables” menu to import variables from an Excel file.
The “Import from Excel” menu has several options that need to be set to read the correct columns and rows from the Excel file (Figure 19):
Figure 19: Use the “Import from Excel” menu to define the rows and columns to be read from the Excel file.
After pressing “OK” on the “Import from Excel” menu, the variable menu will be filled in with the contents of the Excel file (Figure 20):
Figure 20: Use the “Import from Excel” menu to define the rows and columns to be read from the Excel file.
The “Auto update” option is not ON by default. When turned ON, if the contents of the Excel file, the variables will automatically update when running the process.
The Excel file can even be left open and have its contents read.
