Sweep Parameters Tab

Use the Sweep Parameters tab to configure sweep parameters and strategies.

• Number of Test Vectors —(Read-only) Indicates the number of iterations the sweep loop will execute if it runs to completion.
• Errors and Warnings —Visible only when errors or warnings are present. Indicates the number of errors and warnings in the sweep step is shown in the top left corner of this tab. Click on the number to see a list of all errors and warnings, and click on an individual item to highlight the source of the error.

Sweep Parameters Table

This table displays the sweep parameters. It contains the following columns:

• Enable or Disable —Enable or disable a parameter.
  Note You can also enable or disable a parameter by navigating to Properties>>Expressions . Set a pre-expression and set the Parameter to true/false. The expression will run at the start of each loop. This option will enable or disable the parameter at run time, but the edit time view in step settings will not change.
• Parameter Name —Specify a symbolic name for the parameter.
• Nesting Level —View the integer value that indicates the nesting level of the parameter. The default and highest nesting level is 0. This value increases as the nesting level increases. For more information, see the Configuring Parameter Nested Levels section below.
• Type —Select the data type of the parameter. The values that this parameter iterates over must be this type.
  • I/O Session —Sweep on the instrument attributes specified by an I/O Session.
  • All other types —The sweep parameter values of this type are stored in the variable of the same type specified in the Parameter Value/Session column.
    • Number
    • String
    • Boolean
    • Enumeration
  Note When TestStand loads Sweep Loop steps from older versions of TestStand, it evaluates the expressions in the Sweep Strategy and Parameter Value and updates the parameter's Type accordingly. If the Specification property was set to "Expression" in the old step, TestStand updates the parameter's Type based on the values specified in the Strategy options, such as Start, Array, or Constant.
• Write to Output Stream —Check to write this sweep parameter to the output stream specified on the Output tab at the end of each iteration.
  Note This checkbox has no effect if output is disabled.
• Parameter Value/Session —Specify the location to store the sweep parameter value. Select options based on the configuration of the Type column. You can choose a variable of the selected parameter type by launching the Select Variable or Session dialog from the button in Parameter Value/Session.
  • If you configure the sweep parameter as an I/O Session , specify the TestStand variable that stores the I/O session. Available I/O sessions will be listed in the dropdown menu.
  • If you select any other data type, specify a variable of that type to store the parameter value for each iteration of the loop.
• [Count],{Range} —(Read-only) Displays summary information about this sweep parameter.

You can edit the table by clicking the following buttons.

• Add Parameter —Adds a new sweep parameter to the table. The new parameter has the same settings as the selected parameter.
• Add Parameter from CSV File —Imports new sweep parameters to the table from a CSV file. All imported parameters will be added below the selected parameter. Click the dropdown menu beside the Add Parameter icon to access this option.
  Note If Stream parameters already exist in the Step or parameters are nested, this option only allows you to add parameters from the CSV file as an array.
• Remove Parameter —Removes a sweep parameter from the table.
• Move Parameter Up —Moves the selected sweep parameter(s) up one row in the table. You can also move a parameter by dragging it to a new position in the list.
• Move Parameter Down —Moves the selected sweep parameter(s) down one row in the table. You can also move a parameter by dragging it to a new position in the list.
• Indent Parameter Right —Changes the nested level of the selected sweep parameter. See the Configuring Parameter Nested Levels section below.
• Indent Parameter Left —Changes the nested level of the selected sweep parameter. See the Configuring Parameter Nested Levels section below.
• Open Table View —Displays the Test Vector Table or the Value Summary Table.

Automatic Variable Creation

When you specify a parameter name, TestStand automatically creates a variable of the data type that matches the parameter data type. TestStand updates the Parameter Value/Session field to reference this variable. If the parameter is renamed or its type changed, the name or type of the automatically created variable is updated. The type of a variable will not be updated if there are any references to it. The name of a variable will not be updated if there are any unconfirmed references to it.

TestStand creates the variable under one of the following: Locals, Parameters, FileGlobals, or StationGlobals. You can specify where TestStand should create variables by changing the option in Station Options>>Preferences>>Context of Automatically Created Variables .

TestStand does not automatically delete variables that were automatically created in StationGlobals.

An automatically created variable will be deleted under the following conditions:

• The parameter Type changes to Session
• The value changes to reference a different variable
• The parameter is deleted and there are no other references to the variable in the sequence file

Configuring Parameter Nested Levels

Change the nested level of a sweep parameter by moving the parameter to the left or right in the Sweep Parameters Table. Change the level of a parameter to run a parallel or nested sweep.

• Parallel sweep — Run more than one parameter synchronously by assigning the parameters the same nested level. Parameters at the same level will iterate on the same step, and must contain the same number of values.
• Nested sweep — Create nested sweep loops by moving the selected parameter to the right underneath the parameter within which you want to create a nested sweep loop.
  Note You can create nested sweep loops at multiple levels. However, sweep parameter levels must occur in increasing order.

Sweep Parameter Strategy Table

This table displays the strategy settings for the selected sweep parameter. It can contain the following rows:

• Strategy —Specifies the sweep parameter strategy for this parameter. The Strategy row is always present.
• Mode —Specifies whether the values for a Strategy are specified using expressions or constants. If the mode is Static, the Strategy should be specified using constants. If the mode is Dynamic, TestStand expressions, which will be evaluated at run time, can be used to specify the Strategy.
  Note In the case of Dynamic parameters, all values displayed in the panel and the Test Vector Table at edit time can change at run time.
• Start —Specifies the start value for a Start, Stop, Step or Start, Stop, Count strategy.
• Stop —Specifies the stop value for a Start, Stop, Step or Start, Stop, Count strategy.
• Step —Specifies the step value for a Start, Stop, Step strategy. This field is not configurable for the Start, Stop, Count strategy.
• Count —Specifies the number of points for a Start, Stop, Count strategy or the number of array elements for the Array (1D List) strategy. This field is not configurable for the Start, Stop, Step strategy.
• Distribution —Specifies if a Start, Stop, Step strategy is linear or geometric progression, or if a Start, Stop, Count strategy is linear, geometric progression, decade, or octave.
• Numeric Format —Specifies the numeric format of all numeric parameters for all strategies.
• Array —Specifies the array for an Array (1D List) strategy when the Mode is set to Dynamic.
• Constant —Specifies the value for a Constant strategy.
• Field/Column ID —Specifies the field or column of the InputRecordStream specified on the Input tab when using a Stream strategy.
• Values —Lists the values for the parameter, as specified by the strategy. The values shown are read-only for all Strategies except the Array Strategy in Static mode. If you disable any item in the Values list, that item will be discarded when generating the strategy values and the final test vectors.
• Edit as Static Array —Allows you to change the current Strategy to Array and the mode to Static, while retaining the populated values. The values can then be edited like a regular static Array parameter.

This table displays the following additional rows for I/O Sessions:

• Attribute —Specifies the instrument attribute in the session you want to sweep on.
• Channel —Specifies the channel on the instrument you want to sweep on. This setting is available only if the instrument supports multiple channels.
• Variable —Specifies the TestStand variable used to store the sweep values in an iteration.

Values Table

Use this table to view and manipulate the values for the selected sweep parameter. Disable specific values for static arrays. The disabled values will not be used as a part of test vector generation and will not appear in the Value Summary table. The Values table is read-only for all strategies except Array.

Behavior of Dynamic Parameters

Dynamic parameter values use TestStand expressions, which are evaluated at run time. Unlike Static parameter values, the values generated by Dynamic parameters can only be estimated at edit time. This results in the following behavior and functionality:

• In Start, Stop, Step and Start, Stop, Count Strategies, expressions are captured at loop start and not sampled again.
• Values in the Test Vector Table cannot be enabled or disabled.
• Values in the Value Table cannot be manually changed.
• If you rename or change the type of a Dynamic parameter in the Step Settings, the Test Vector Table will be marked as out of sync. Refresh the table to reflect your changes.

See Also

Sweep Loop Step

Sweep Loop Input Tab

Sweep Loop Output Tab