A few (!) TestStand questions from a TS Newbie

[Marlon Persaud]

I am developing a two PC test system which will have TestStand on a MasterPC and the TS remote engine running tests on a SlavePC. The tests are being developed in LV and I have a VB UI controlling the TestStand API. I have generated a palette of company specific code templates and step types which have custom fields detailing my test parameters. When (if?) we hand over the test system we want our customers Test Engineer to edit and create custom test sequences from our palette of test types.

My questions are:-

1. How do I pass variables from one sequence to another (for example from a master sequence into remote sequences) in TestStand? I know about globals/locals, but is there another way? These variables shouldnt be defined as globals, they are test specific and will change from sequence to sequence. The Test Engineer should also be able to modify any test parameter from the top level main sequence, without having to delve into the remote sequences and modifying them.

Alternatively am I able to run remote tests rather than remote sequences. This would then allow me to access the variables directly in the MasterPC sequence editor.

2.Is there a way I can access the Sequence Context variables (which I have created with my custom test type) directly in LabView (Like the Input Buffer for example, which doesnt require any unpacking at the Labview level, it just appears on the front panel). I know how to access the Sequence Context using property nodes etc.

3. Can I calculate the total number of steps in a sequence (including those in remote sequences?) this is to be used for generating a usable progress bar independent of the sequence and number of Vis (I have used Thread.PostUIMessages to post back an increment event in the UI, but this could go over the reported number of test steps).

4. Can I create a step post action that automatically posts a UImessage to update the UI progress bar? (This would remove the need for number 3 in every VI)

5. Is the Remote engine killed after the end of execution? (after going through the two pass shutdown method on the MasterPC.) Can it be started remotely?

Thanks in advance!

Marlon Persaud
Test Development Engineer

[RayFarmer]

Hi,

Q1. Each sequence you have the Step Groups, Locals and Parameters, when viewed in the sequence editor. When you Specify a SequenceCall, On the bottom half of the dialog box is a list of Parameters. These parameters are picked up from the Sequence's Parameters. If you have no parameters defined in your Sequence, then no parameters will be available when you are specifying a SequenceCall.
If you are executing a Sequence by way of the NewExcution API function, then this has an arg which you can use to pass a container of the Parameters' Listed of a sequence.
If you do a search in the Resource Library for "passing parameters to a sequence", you should find some useful examples which will help.

Q2. There are a series a VI's that are installed into your LabVI
EW folder in the USER pallete when you install TestStand. These allow you to read/write to a property/variable knowing the LookupString. eg "Step.Limits.Hi" whould enable to read or write to the current step's upper limit if the Step was a NumericTestLimit type.

Q3. You could scan through the RunState.SequenceFile and the RunState.SequenceFile.RunState.Caller properties, if the step is a SequenceCall, and count the steps in each group or just the Main step groups. This will give you a total count you require.

Q4. Yes. When you create your custom step type. Not only can you define the call for the action of the step. but also the Pre Step action and the Post Step action. Its a similar process to define the Pre and Post Actions of a step as it is the Main action.

Hope this helps
Ray Farmer

PS can not offer an answer to Q5 as I haven't used the remote interface.

[Marlon Persaud]

Thanks Ray,

Thats definitely made a few things a lot clearer. Once I have finished coding that lot then I'll be back with some more questions no doubt!

Thanks
Marlon