stop and reset data acquisition

[Ronster]

I have a vi that takes raw vibration signals and filters, integrates and then displays.  The user watches the live display and then when ready clicks on the 'acquire' button.  The data is averaged and saved.  The user is then asked if they want to acquire more data.  My problem is when the 'live' screen comes back, there is a huge curved slope.  How do I reset the data acquisition?

Ron

[RavensFan]

I'm not sure what you mean by a live screen and a huge slope.  Perhaps you can post some screenshots of your front panel showing this.  Also post your VI's.  If you run your VI's and they show this.  Stop the VI, select make current values default, and save the VI and post that.  That way there is real data on the front panel that can be looked at.

[Ronster]

As usual, if I bang on a problem long enough, I find my mistake.  I  just changed my DAQ Assistant setup to be N samples instead of continuous.  I was getting a discontinous spike when my vi went back to 'live' data from my averaged spectrum.  Thanks for the reply.

Go Ravens!  As an Eagles fan, you can imagine my crushed ego at this point.  Well, the Eagles put Rothlesberger on his back 9 times!!!  Go get 'em.

[Coq_Rouge]

Your problem is that your buffer han been filled up and overflowed while waiting for user to deside what to do. This problem can be solved if you do a "dummy read" with the number of samples per channel input unwired or set it to -1. If the task acquires samples continuously and you set this input to -1, this VI reads all the samples currently available in the buffer. Do the dummy read then you leave your saving routine. And you will start with a fresh buffer in the "live" screen. After all your application is a continuously reading type application 

[Ronster]

Thanks!  It's working fine.   Please excuse this question.  The answer is probably very obvious, but not to me.  I am using the Extract Single Tone Measurement vi to find a peak based on an approx. input from the user.  There is an approx. freq input, but it is bundled with an input for percentage bandwidth.  How do I get the user input into the express vi?  When I try to move just the approx. freq input out, the vi won't let me.

[Coq_Rouge]

I consider most of the Express VIs to be flimflams. So I do not use them very often. First of all get rid of the Express VI by converting it to a standard VI. You do this by right clicking on it. Select open front panel. Now you have a standard VI you can work with (rember to save the new VIs). This will not destroy the Express VI.

Good luck

Message Edited by t06afre on 01-29-2009 03:10 PM

[Ronster]

Will do!

[Ronster]

Hey Coq Rogue,

I know what you have described is the answer to my DC ramp on returning to 'live' mode, but your verbage leaves me in the dust.  What do you mean by a 'dummy read'?  What is the LabVIEW name for this task?

Ron