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How to set up for flow meter using liters per pulse as signal input

Hi,

 

I am working on my final project in Mechanical Engineering and am trying to set up a flow meter system with no luck.

 

I am using this flow meter FLOWFUEL30L0 with either a USB-6008 or myDAQ.  I am using labview 2010 or 2012. 

 

The sensor outputs as liters/counts.  From my understanding, the 6008 is unable to handle this but the myDAQ can.  If I am wrong, please let me know. 

 

 

I need to set up a VI that collects this voltage pulse from the sensor and turns it into a flow rate.  All I have been able to accomplish so far is collect the number of pulses that occured over a data collection.  I envision that there must be some way to code the VI so that say every .1 seconds the VI takes the number of counts and divides by that .1 seconds so that I have a flow rate that represents what was happening for that specific .1s.

 

Let me know if this is unclear and I will do my best to clean it up.

 

 

Thank you,

 

Will

 

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Here is the most recent iteration of the VI our team is trying to use.

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take your total count divided by a running timer in the main vi, that will give you a flow data...6009 cannot give you frequency

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That would only give an average for the entire run, I need flow values at time steps throughout the data collection.

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If you are able to get the value as a counter (apparently yes), then all you're missing is the timing information. You won't get too accurate timing data with the 6009, but if your time resolution is low enough then it should be fine.

 

What you can do is this - with each read, take the value of the counter and call the Tick Count primitive, bundle their data into a cluster and throw that into a queue. Then, in another loop, you can regularly get the queue status (wire T to the Return Elements input) and this will give you the history of all the data. You can now take the last one, go N readings back and do your calculations on the time/counter combo.

 

Note that this can produce fluctuations in your flow rate, depending on the time resoltion, measurement speed and actual number of pulses per measurement. You might have to only check flow rate every 1 or 2 seconds or to perform some smoothing on the data (such a a running average).


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