Intro

A known scenario in TestStand is that in some cases it make sense to loop step(s) during a test execution. An example of this is during Burn In or Environmental tests of Unit(s) (UUT), often testing several UUTs simultaneously (Batch or Parallel model). In this case, UUTs are tested for several hours with different surrounding temperature(s), potentially generating massive amount of data. 
Other scenarios is looping steps for a single UUT during functional test generating a lot of step results in the UUT report.

This article will use Burn In test as example, but the methodology discussed below are applicable in many other scenarios. Also, TestStand has a step looping property that is not included in these discussions.

Test Procedure

A simple procedure may be to test the UUTs 5 Volt and 24 Volt output for several hours under a certain surrounding temperature. For each measurement, some action steps should be applied:

• Set chamber temp = 40°C
• Loop for 2 hours
  • Wait 1 minute
  • Action Steps ...
  • Measure 5V @ 40°C
  • Action Steps ...
  • Measure 24V @ 40°C
• Set chamber temp = 60°C
• Loop for 2 hours 
• etc.

Running the loop every minute will result in 120 loops and if you log each step, this will result in 720 steps (including loop steps).

TestStand example:

Implementing this in TestStand using Flow Control steps may look like this:

UUT Report in WATS:

A better practice is to Disable ALL logging inside the loop, temporarily log the results to a local Array, and add Summary steps after the loop.

The UUT report in WATS:

The report will only contain a few steps and give a better overview. By Using the XYGraph Multiple numeric limit test added by WATS, you can get a nice overview of the measured value over time.

Conclusion

The example above is a simple version of a test sequence, and often you find yourself in a lot more complex solution. But in many cases, the same methodology applies where disabling result logging within a loop and add summary steps will make a lot more sense from a analyzing point of view.