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DAQmx Data Acquisition

Hi guys. 


I need an opinion an some ideas actually. I would like to grab a signal of Pressure and also Crank Angle using Pressure Sensor and Angle Encoder respectively. 


Thus, as far as I know, we have to use DAQmx to grab the signal. I already have NI USB 6009 for my project. And I already designed the VIs. (Please refer to the attachment)


HOWEVER, when I testing my design using a signal generator, the output shown was not as expected. 


The first case structure is used to acquire data from sensor.


I use a control of Number of Cycles and Number of Elements (per cycle) so that the user would be control the number of cycles for the crank by themselves.


It seems that it was not working as wanted.


I'm really hoping someone to help me solving this problem.


Thank you.



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The first thing you should do is eliminate ALL local variables. You have at least one race condition and there could very well be more. Create a cluster to hold all of your data and use a shift register to pass it from state to state. In each state, unbundle by name or bundle by name as needed.


If you continue to have problems, you then need to provide details on 'it was not working as wanted'. That's pretty meaningless. You are the only one that knows what you want. You have to be able describe what you want and what's the difference with what you are getting.

Message Edited by Dennis Knutson on 06-23-2009 08:37 AM
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Ok Dennis.


Thanks a lot. I will work on it again and let u guys know if i have a problem with it.



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By the way Dennis, I need your idea.


Let say, I have an array of :

Index      Value 

   0           1

   1           2

   2           3

   3           1

   4           2

   5           3

   6           1

   7           2

   8           3


Then, number 1 is the reference point. What will you do (in LabVIEW) to detect the reference point of number 1 at Index 3 and others. 


I would much more appreciated if you could show me an example to do this (picture may be).



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