Testing Car Wash Application In Test Stand

[NagRaj]

Hi All,

I am a new user to Test Stand. I want to test Car Wash Application, is an example application, which can be found in NI site. I tried it in Test Stand but it is giving some problems. First for this application I have created connector pane in LabVIEW. Next in Test Stand in a test step I have specified the module. Then I have given Inputs for Purchase selection cluster and Car Wash Simulation Switches cluster. When I run it Test Stand is able to supply input for Purchase Selection cluster( 5 $ and 3 $). But after that it is not applying inputs for Car Wash Simulation Switches cluster. Can anyone help me how to do this in Test Stand?

Attached is the screen shot of application. I am also attaching application description doc for your reference. So please help me in testing this application.

Regards,

Nagaraju

[Dennis_Knutson]

Look at the initialize state in the VI and you will see that the simulation switches are all set to false through a local variable. So, it doesn't matter what values you pass through TestStand. If you remove the local variable, you will see the switches set to whatever you set them to in TestStand.

[NagRaj]

Hi Dennis,

Thanks for the reply. It is working fine when I remove the local variable. But the problem is till I select any operation (5 $ or 3 $) in Purchase Selection cluster, the Car Wash Simulation Switches should not be operable. Means till you select a 5 $ or 3 $ operation those should not be made true. That's why there is a local variable whose value is set with "False" in initialization part. Could you tell me any alternative solution?

One more thing, I am unable to stop the application from Test Stand. Means in the Test Step I have given inputs for Purchase Selection Cluster and Car Wash Simulation Switches cluster. So when I execute this Test Step without local variable it is executing fine. But I am unable to stop the application to run another Test Step. Could you please tell me how to do this?

Regards,

Nagaraju

[Dennis_Knutson]

Is there some particular reason you used the car wash example in TestStand or was it just some random VI you picked? I wouldn't say that this VI would be typical of TestStand steps. In order to use this VI, you have to make the front panel visible and then some person is going to have to click on the stop button in order to return to TestStand. There are ways to make this work but is that really what you need to do? Since you are a new user, have you looked at the shipping examples? With few exceptions, a step would perform some sort of operation and return to TestStand without a user intervention. That means a VI without an event structure and if there is a while loop, it is running a state machine perhaps. Are you also a new LabVIEW user?

[NagRaj]

Hi Dennis,

Thank you very much for your quick and fast reply. Ya, I am a new user to both LabVIEW and Test Stand. Our Lead asked us first to implement the Car Wash application in LabVIEW and then to test it in Test Stand.

That's why I chose this application. There should not be any manual operation in LabVIEW. Everything should be automated. Even the stop button also. The user have to give inputs in test steps. LabVIEW should take those inputs, execute, then it has to stop the application and Test Stand should unload all the modules.

So please tell me a way to achieve this, as this is a starting step for us to automate another big application.

[Dennis_Knutson]

I would modify the VI so that it would not need the stop button at all. There would be some fairly significant changes required to the VI so that it would start automatically and run based on just the purchase selection value you pass from TestStand.  That means making it a simple state machine where there would be no 'Wait for Wash Selection' state and going to the 'Exit' state would not rely on the stop button. This VI is really a poor example to use as is. Does this 'lead' of yours have any TestStand or LabVIEW experience?

[NagRaj]

Hi Dennis,

Thank you for the reply.

Ya he knows LabVIEW very well. But till now we worked on C and C++ and we are very new to LabVIEW. That's why he gave very simple example.

Actually he knows the code is available in NI site. That's why he told us to not to use that code and we should implement it on our own.

When we did it we have not used "wait for wash selection" state machine state. We just kept a case structure, where if u dont select any purchase selection it will be in initialize state only. Like that we did with simple shift registers and not the standard like the code which NI site is having.

Lead gave this simple example to know how we will test this application. So please tell me how to proceed in elaborated manner.

Once again thank you very much for your replies.

[Dennis_Knutson]

Well, it sounds like your lead wants you do the work yourself as a learning exercise. That may help you learn a little about LabVIEW but I still think the car wash example is all that applicable to the typical TestStand code you will eventually be writing.

What you will need to do to run the whole thing from TestStand is to first eliminate the local variable write in the initialize state as I mentioned. Then, you are going to have to modify the last states of the deluxe and ecomony selections so that the exit state is called automatically. When this is done, you can call the VI and get the results (such as they are) inot TestStand. You really can't call the VI and then change the front panel controls from TestStand easily. That would require you to start up another VI in parallel (i.e. in another thread) and use VI Server to control the car wash VI.

[Dennis_Knutson]

Going back and thinking about what you've posted, I'm wondering if you intend to use TestStand as a sort of software verification/validation tool. If that's the case, then you have a lot of work ahead of you. TestStand wasn't really designed to do that and imho, is a pretty poor choice if you want to do this on any sort of program that has a GUI. See this.

[NagRaj]

Hi Dennis,

Really very thankful to you for your help and suggestions.

Just now I saw your reply and let me understand the link you have provided.

Once I done, I will tell about the application.

Thank you once again.....