Labview Program for acquiring two values after a given period of time

[kranti747]

Hi

I am a final year student working on a project.

I want to make a vi which will measure two readings of the data such that the first reading is the initial reading and the second reading is after a certain period of time.

Basically I want  to measure fuel flow using a strain gauge. The concept is that a small fuel tank is fitted on the strain gauge. At first the fuel tank will be full (note: this will be the first reading) and after 60 Seconds there will be a decrease in weight of the fuel tank due to fuel consumption (note: this will be the second reading).

I want to subtract the final reading from the initial reading and divide the answer by 60.

Please tell me how to do this.

Thank you.

The hardware I am using is chassis cdaq9172 and Ni 9129.

[crossrulz]

Let's start from the beginning.  Do you know how to take a measurement?  I see you are using a strain gauge, but how are you reading it?  DAQ?  DMM?

[kranti747]

well i am using a four wire strain gauge and interfacing it using ni9219 in cdaq 9178 chassis. I am using a DAQ.

Thank you very much for your reply. I am a begineer. 

[crossrulz]

I would setup the DAQmx task to sample every 100ms for 1 minute (600 samples).  Tell the task to run, wait the 60 seconds, read the data, do your math on the 0 and 599 indecies.

[kranti747]

Will you please tell me how to do so?

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crossrulz wrote:

I would setup the DAQmx task to sample every 100ms for 1 minute (600 samples).  Tell the task to run, wait the 60 seconds, read the data, do your math on the 0 and 599 indecies.

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[crossrulz]

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@kranti747 wrote:

Will you please tell me how to do so?

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[kranti747]

Thank you  very much. I really appreciate your help. 

Thanks a a lot.

[kranti747]

Hello crossrulz

I have tried to make this in Labview 2009 but I am finding it hard to make the VI as I am not professional in using Labview 2009.

CAn you please explain further so that I can make this VI in labview 2009.