Advice for Generic Controller and Test Machine in LabVIEW

[lvb]

I am fairly new to LabVIEW (6 months) and looking for a solution for test and measurement. There are a few types of tests that we run: state machines (wait for a certain set of digital inputs), ramping tests (increase output until certain input is hit), and position/voltage control (maintain a position/load/acceleration) and also log test data to a database. I would like to create an environment where a user could “program” a test with ease. We currently have the capability of a state machine with digital inputs, but lack the ramping and position/voltage control. I was wondering if the community here could recommend some examples/solutions for this type of application. Also, I was wondering if anyone has examples/resources that allow a user that has no LabVIEW experience to “program” this type of machine. Basically to create an environment where the user could select certain steps in a sequence and have that sequence repeat, for example:

Step 1. Output the voltage on channel "n" to 10.0 V

Step 2. Wait for digital input "x" to turn on

Step 3. Increase the voltage on channel "n" at "y" Volts/Sec

Warning: this is also cross-posted in the official ni forums, but I figured I should try to get feedback from both communities. Please respond with your advice!

Thanks,

Brian

[WMassey]

I recently built a LabVIEW application which would allow a group of mechanical technicians to cycle several axes of motion through whatever different positions they might choose, acquiring position data at points they specify, to check the repeatability of the system. They seemed quite pleased with it (but who wouldn't be after having to do this with individually-input positioning commands and pencil & paper).

It was definitely not a beginner-level LabVIEW program but it wasn't too difficult either. It did make use of the LabVIEW state machine concept (it couldn't have been built otherwise). The operator is presented with a "listbox" that he can populate with program steps. He highlights a line in the listbox and then chooses an action to perform from an enumerated list of actions below the listbox. Depending on what action is chosen, other controls specific to that action then appear to let him specify the details of the action. After he is finished detailing one step he selects another line in the listbox and repeats the process until his "program" is finished.

The LabVIEW programmer has to ensure that all possible actions that the operator might need are available in the listbox. You may want to include "repeat" as one of the actions available with arguments of which step to repeat to and how many times to repeat. Give the operator the ability to save, recall and edit the sequences he assembles. When the program is run it just steps down through the list of actions, jumping to whichever state machine state performs that action. It won't be very difficult to add new actions in the future if they are needed; it'll just mean a new item on the list of actions and a new state to handle it (and a conversion routine to convert the old saved-sequence files to work with the new data structure action).

Yes it is possible using basic LabVIEW.

No it is not something that comes pre-assembled.

NI's "Test Stand" software may provide you with more out-of-the-box functionality in this area.

[lvb]

I took a look at NI's Test Stand, but it seems to be more complex than I want the technicians to deal with. Any chance you could post/e-mail some of your block diagrams for reference? I am looking to do the exact same type of application.

Any one else have some examples of such an application?

Thanks!

[WMassey]

I took a look at NI's Test Stand, but it seems to be more complex than I want the technicians to deal with. Any chance you could post/e-mail some of your block diagrams for reference? I am looking to do the exact same type of application.

Any one else have some examples of such an application?

Thanks!

I would post it but even with all the motion control VIs gutted and the OpenG VIs removed it's still 122 files and about 3Mb when zipped and that is more than I'm allowed to attach to a posting here. Send me a private message (click on my user name) with your email address and I'll try sending it that way.