Parallel and Synchronized Multi UUT's Test

[Eng. Salman]

Hi,

We have more than 150 tests should be applied to verify our product and we have big quantity to be tested in short period.

For this purpose I decided to test 4 UUT's at a time using suitable configuration. I have heart that Test Stand can meet the requirements and I have red TS help (batch & parallel test) but I get confused since I'm not expert in TS.

To make it clear I have:

*4 DMMs

* 4 set of switches and relays to apply 4 tests at a time.

* shared sources (AC PSU, DC PSU, FGen) that can feed 4 UUT at time.

What I'm looking for is:

• Is it possible to apply 4 tests at a time using TS? (I think yes)

• Since I have shared power sources, can I synchronize all the UUT's to be at the same step? (I mean all 4 UUT's should start step1 and wait till all finishes step 1 to start step 2.)

• When any UUT3 fail, UUT3 test stops and other tests should complete the whole sequence.

• I have already developed TS sequence that call group of sub-vi's to test single UUT at time.

Knowing the previous points what is the right way to apply my test?

Help me please.

Thanks

[AndrewMc]

It's great that you've chosen TestStand as your Multi-Head testing platform.  It does provide some great functionality, but let's outline the idea and answer your questions.

With the parallel and batch models, TestStand is able to execute your sequence on X number of UUTs simulatenously.  This will be taking advantage of multithreading on your computer to ensure that the CPU is taken full advantage of.  It's important to note some points with multi-UUT testing.  Your hardware most likely has limitations that define it as an exclusive resource, such that it can only be accessed by one UUT at a time.  We have a mechanism in TestStand (Synchronization step types) to ensure that multiple UUTs do not try to access the resource at the same time.  You mention that you are using switches depending on the UUT.  One feature that you might want to employ if you are using an NI switch (or in some cases even if you aren't) is Switch Executive (another NI product); this would enable you to simply check a box that says "Use Switching" and select a particular "route" to be connected for particular step(s).

To answer your needs specifically:
1) Is it possible to apply 4 tests at a time using TS?
Yes
2) Since I have shared power sources, can I synchronize all the UUT's to be at the same step? (I mean all 4 UUT's should start step1 and wait till all finishes step 1 to start step 2). 
The Synchronization step types should benefit you here.  Specifically, you can use a Rendezvous and, if using the Batch model, Batch Synchronization sections (or step properties).
3) When any UUT3 fail, UUT3 test stops and other tests should complete the whole sequence.
This is the default behavior.
4) Knowing the previous points what is the right way to apply my test?
I'm not sure what specifically you're looking for, but if I understand correctly, system design is completely dependent on your whole test requirements.  I would encourage you to check into TestStand I and II training courses to get the necessary foundation to make those architectural decisions.

Hope this helps!

[Eng. Salman]

Thank you very much Andy for you supports.

Your information is very helpful and it encourages me to deeply go through Test Stand.

I would like to clarify the image here.

·         4 UUT to be tested at the same time.

·          The test contains many main steps which include group of measuring points.

·         Every main step consist of Two stages:

o        1^st: setup and powering stage. (Shared for all 4 UUT)

o        2^nd: Measurements stage. (each UUT has its own DMM and group of switches)

·         The powering stage should be implemented at the beginning of each main step ones for all UUT.

·         The measuring stage will be implemented for each UUT and for each measuring point till main stage terminate.

·         When all UUT terminate the First main step, new main step starts with new setup and powering stage.

  Could you please advice me what to do?

Thanks & Regards

[AndrewMc]

That sounds like correct structure.  Some additional points as you go through this:

1. These "Setup and Powering" steps are usually done inside of the Setup step group of a sequence.  You might consider creating a sequence for each of these multi-stage operations such that each has its own "Setup and Powering" group of steps and then the Main group of steps (your "Measurements" steps).
2. It looks like you're probably wanting to use the batch process model.  As well, if in fact you want step failures to stop the whole test, you might want to configure the station option (Configure>>Station Options) to set "Immediately go to cleanup on Sequence Failure" (checkbox at the bottom).
   

Message Edited by AndrewMc on 12-04-2007 05:52 PM