Multiple Numeric Limit Test Step Type - LabWindows/CVI

Purpose

This example demonstrates how to use a Multiple Numeric Limit Test step with a LabWindows/CVI code module.

Example File Location

<TestStand Public>\Examples\Built-In Step Types\Multiple Numeric Limit Test Step Type\CVI\Multiple Numeric Limit Step Type.seq

Highlighted Features

Multiple Numeric Limit Test steps

Major API

None

Prerequisites

You must have the LabWindows/CVI Run-Time Engine installed and you must configure the LabWindows/CVI Adapter to execute steps in-process. If you want to use the Execute Steps in an External Instance of CVI option, you must have the LabWindows/CVI development environment installed.

How to Use This Example

This example contains four Multiple Numeric Limit Test steps. The first three steps obtain four measurement values and compare them to the following high and low values specified on the Limits tab of the Step Settings pane:

Each step demonstrates a different way of using the Multiple Numeric Limit Test step functionality.

• The first step, Multiple Numeric Limit Test 1, calls a code module that inserts the measurement values one element at a time into the Step.NumericArray property. For example, the step inserts the value for the VOLTAGE 0 measurement in Step.NumericArray[0], inserts the value for the VOLTAGE 1 measurement in Step.NumericArray[1], and so on, as shown on the Data Source tab of the Step Settings pane.
• The second step, Multiple Numeric Limit Test 2, calls a code module that writes a single numeric array to the Step.NumericArray property instead of writing the four array elements individually.
• The third step, Multiple Numeric Limit Test 3, uses the <None> Adapter and therefore does not call a code module. The Data Source tab of the Step Settings pane for this step shows that the step obtains measurement values from local variables such as Locals.Voltage0, Locals.Voltage1, and so on instead of from the Step.NumericArray property. The Statement steps in the Setup step group use expressions to assign these variables.
• The fourth step, Multiple Numeric Limit Test 4, is similar to the third step, but demonstrates the new EQ+/- comparison type supported by TestStand 2016 and later. See the table below for more information about this step's threshold values.

For a Multiple Numeric Limit Test step to pass, every test in the step must pass. You can try changing a limit to cause a test to fail, but ensure that you do not save any changes to the sequence file before executing the sequence or closing the sequence file.