Showing results for 
Search instead for 
Did you mean: 

Latency in data acquisition

Hello Everyone, 


I am a new member of NI and just started my first VI, pretty basic one made for testing interlinearity of dual crossed analog signal given by the position of a joystick.


Attached you can find my VI,I would imagine the way i did is flawed but broadly works according what i want except the fact i have a short time of missing data periodically, as shown on this following graph screen shot (but also noticed on the excel file saved):


Graph screen shot.png

So my question comes, this latency is due to the way I process the signal using DAQ mesurement or the way i save the file might conflict with a loop ?


If you have any idea or suggestion, i would appreciate your help. 

Thank you. 




0 Kudos
Message 1 of 4

For a new developer that's really not all that bad.  But, it does have problems! I'm sure someone will be by with links to training resources.  Listen to them - you do need training.


Your worst problem is that you have mixed up the User Interface (all those dialog vis) and the Acquisition loop.  essentially you pause the DAQmx acquisition while those dialogs display.  That is bad.

"Should be" isn't "Is" -Jay
0 Kudos
Message 2 of 4

Building on what Jeff·Þ·Bohrer said... You should consider a Producer-Consumer arcetecture.


That way your DAQ is always running in the Producer loop and you deal with user interface and saving data in the Consumer loop.

=== Engineer Ambiguously ===
0 Kudos
Message 3 of 4

OK, thank you very much guys.


Now, I understand in which direction I have to organise my architecture.

NI has some good illustrative exemple of Producer/Consumer.  

0 Kudos
Message 4 of 4