subtracting voltage readings in DAQ assistant

[mas4444]

I am trying to "build" a mass flow meter using a load cell and LabVIEW.  I am trying to read in weight values from an oil cylinder that is losing mass over time.  I want to read these weights from the load cell into DAQ Assistant and find the difference in load values over a given time interval and compute mass flow out of the oil cylinder using this data.  I have done a fair bit of searching on the boards and it looks that arrays are the way to go.  As I am very new to LabVIEW, I am curious if there is an easy way to accomplish this.

Thanks for any advice,

Matt

[Otis]

Hi Matt,

That shouldn't be too much of a problem at all. 

Flow is simply the amount of something at Time Y minus the amount at Time X over the amount of time elapsed (Y-X/dt).

Essentailly all you have to do is calculate the difference between one measurement and the next.  Since you already have a dt calculated by the sample rate (e.g. rate of 1000 Hz => dt = 1ms).  So all you need to do is find the difference between one value returned and the value before it and divide that by dt.  Viola, you're done.

Shouldn't be too hard.  You do most things in LabVIEW just like you would anywhere else.  So figure out how to do it first, then make it work in LabVIEW.  Normally I'd write up some code, but I'm a bit short on time today.

Regards,