read specification cluster from LVM file

[Andy Peters]

Does anyone have a clever solution to programmatically read limit specification masks (for waveform limit tests) from an LVM file?

I used the "Mask and Limit Testing" Express VI to create the masks, which I saved as LVM using the save-data feature.

I don't want to use the Express VI to do the actual test because the testing is in a subVI that's called within a loop; each iteration of the loop needs to send different masks to the Limit Test.vi that's in my subVI.

Thanks,

-a

[DavidJCrawford · Accepted solution]

Hi Andy,

 The LVM is a text file so you can read that in using read file function.

After that I search the string to find where the data starts using Match Pattern

You then process the remainder of the file string and then use Speadsheet String to Array with a tab as its delimiter. 

There are tabs at the start of each line and extra line-feed at the end so I used array subset to avoid those areas. This might not work each time but you can fix that when you run into a problem.

 

cheers

David

Message Edited by David Crawford on 11-05-2009 10:01 PM

[Andy Peters]

Hi, David,

Yeah, that works!

Perchance, do you know the difference between the Create Continuous Mask variant of the Limit Specification.vi and Create Segmented Mask variant? The help entry is remarkably unhelpful -- the descriptions of the two are identical! Specifically, it describes the Specification Cluster input as being the same for both, but that's not true -- the segmented version accepts an array of clusters of arrays, wherease the continuous version accepts simply a cluster of arrays. Other than that difference, there's no description of how to actually use either. Yeeesh.

Thanks,

-a

[DavidJCrawford]

Hi Andy,

The polymorphic instance Create Continuous Mask.vi has only one line segment. So thats a cluster of x-array and y-array that you use to limit check all yourwaveform data.

The polymorphic instance Create Segmented Mask.vi has one of more line segment. So thats an array of cluster of x-array and y-array which can be used to only limit check parts of your waveform and ignore the other segments.

NI Example Finder has a couple of examples that include the Limit Specification.vi you should take a look at those.

cheers

David

[Andy Peters]

---

David Crawford wrote:

Hi Andy,

The polymorphic instance Create Continuous Mask.vi has only one line segment. So thats a cluster of x-array and y-array that you use to limit check all yourwaveform data.

The polymorphic instance Create Segmented Mask.vi has one of more line segment. So thats an array of cluster of x-array and y-array which can be used to only limit check parts of your waveform and ignore the other segments.

---

How does one file an Enhancement Request (bug report)? The documentation for this VI is wrong -- it gives the same arguments for both flavors. And it doesn't explain the difference between the two at all.

In any event, the continuous flavor is what I need. Thanks!

-a