LabVIEW

cancel
Showing results for 
Search instead for 
Did you mean: 

time delay probelm in data aquirsition of voltage measurement

Hi,
 
I am measuring voltage using NI DAQPad-6015. Without time delay loop, I can get the data. But what I want to do is to compare the data with that of following moment.
The delay time loop is used to aquire the next moment data.  With this loop, it just stay at DAQmx AI Voltage. What's the problem?
 
Attachment is my program. 
0 Kudos
Message 1 of 11
(3,620 Views)

And I use software LABView 7.1 .

 

Thanks in Advance

0 Kudos
Message 2 of 11
(3,612 Views)
You can't see any measure because your  are runing first the funcion Daqmx Clear Task, this function clears the measurements you take..
 
I send you the next image. I hope this can help you.. 
 
Best Regarts Frank..
 
0 Kudos
Message 3 of 11
(3,606 Views)

Got it. It works. Thanks a lot. 

 BTW: what are the differences among Wait(ms), Wait Until Next ms Multiple , Time Delay?

 

Alyssa

 

0 Kudos
Message 4 of 11
(3,586 Views)

And it is supposed that if the difference of two data is less than 0.05, it will stop aquiring data. but when the program executes, it won't stop. what's the problem?

 

Alyssa

0 Kudos
Message 5 of 11
(3,582 Views)
does anybody know about this? I am waiting online. Thanks
0 Kudos
Message 6 of 11
(3,574 Views)
How did you modify your VI? The first one you posted did not work at all so I assume you reworked it. Post the latest version.
0 Kudos
Message 7 of 11
(3,571 Views)
Thank for your kind reply. Here is the latest version.
0 Kudos
Message 8 of 11
(3,568 Views)

With simulated data, it stops for me. You have your limit set to .01. As long as consecutive measurements are with that range, the VI will stop. Maybe you should or the stop condition with a front panel Boolean and a timer. At least then you can stop the while loop without clicking the Abort button.

p.s. The way that you are creating the array that gets passed to the Write to Spreadsheet File is not necessary. Just wire the value from the DAQmx Read to the edge of the while loop and on the exit tunnel, select Enable Indexing.

0 Kudos
Message 9 of 11
(3,565 Views)
Thanks Dennis
 
Truely it works. One more question: as you suggested I wired the write file function with the while loop. but why the output data is only one. what I want is to storage all the data before it stops.
 
Thank for your help
 
Alyssa
0 Kudos
Message 10 of 11
(3,550 Views)