Purpose

This example demonstrates use of the Parallel process model to test multiple UUTs in parallel. With the Parallel process model, each UUT executes independently, and you can start and stop testing on any test socket at any time.

Example File Location

<TestStand Public>\Examples\Parallel Testing\Testing UUTs in Parallel - Parallel Model\Testing UUTs in Parallel - Parallel Model.seq

Highlighted Features

Parallel process model

Major API

None

Prerequisites

None

How to Use This Example

Complete the following steps to review the sequences and steps in the example.

  1. Open Testing UUTs in Parallel - Parallel Model.seq, select Edit»Sequence File Properties and click the Advanced tab. The settings on this tab specify that the Parallel process model executes this sequence file. You can configure any sequence file to use the Parallel process model by opening the file, navigating to the Advanced tab of the Sequence File Properties dialog box, selecting Require Specific Model for the Model Option setting, and then selecting ParallelModel.seq from the Model File control.
  2. On the Sequences pane, select the MainSequence. This sequence contains one Sequence Call step and one Numeric Limit Test with an associated LabWindows\CVI code module.
  3. On the Sequences pane, select the PreUUTLoop sequence. This sequence is a callback from the Parallel process model. Steps in this sequence execute this code only once before any UUTs are tested. The Set Chamber Temperature step simulates a setup operation that must be performed to prepare the test station for UUT testing, but it needs to be performed only once before any tests begin.
  4. On the Sequences pane, select the Pulse Test sequence. This sequence simulates a test that can execute on only one test socket at a time. In many cases, a test station testing multiple UUTs in parallel must share resources (such as hardware) between test sockets to ensure multiple sockets do not attempt to access the resource at the same time.
  5. Observe the Enter Locked Section step at the beginning of the sequence and the Exit Locked Section step at the end of the sequence. These steps use the Lock synchronization object in TestStand to ensure only one test socket executes this sequence at a time.

Complete the following steps to run the example.

  1. Select Execute»Test UUTs to run the sequence.
  2. The Set Chamber Temperature dialog box indicates the simulated chamber heating process. This code executes before any UUTs are tested.
  3. The UUT Information dialog box displays once the chamber heating process is complete. Use this dialog box to enter a serial number for the UUT and start or stop the execution for each test socket.
  4. Once testing has started on a test socket, dialog boxes indicate the status of the tests. Observe that the Parallel model allows each UUT to start and stop testing independently. However, the Lock steps in the Pulse Test sequence cause that sequence to execute on only one test socket at a time. This behavior demonstrates the ability to synchronize among test sockets when using the Parallel model.