How do you convert voltage from flowmeter to gpm ?

[edholderman]

I am reading a voltage from a flowmeter and trying to convert into gpm and display it in labview? any idea how i convert

[AnalogKid2DigitalMan]

Read the specifications for your meter- it should show the conversion factor to apply (ie 1V/gallon or 5gallons/volt for example)

-AK2DM

[MattBradley]

Do you have the model number and vendor of your flowmeter?

In all probability, it will be a simple linear relationship: GPM = C0 + C1*volts.  So we just need to find out C0 and C1.

[edholderman]

Yes. its a GPI - GNT-200   www.gpi.net

They do have some conversions in the manual, but not for volts (that i can see anyhow) and thats the only readings i have right now. thanks

[walter-donovan]

Right on the website you linked is a video showing how to calibrate their meters. Did you watch it? It says that output is in pulses per gallon (not volts) and the calibration number is printed right on the back of the meter.

[Ray.R]

Yep..  it is usually pulses per gallon (or litres).

The video can be seen here: http://www.youtube.com/user/GPIFlowMeters

or here:  http://gpimeters.wordpress.com/2009/03/13/how-to-calibrate-a-flow-meter/

[Wayne.C]

edholderm,

As previously stated most flowmetes put out pulses and come with a cal sheet that gives the K factor ( # pulses per unit of volume ).  Some flowmeters come with electronics that output 4-20mA or 0-10V.  What is full model # of flowmeter.  What is full model # of electronics that you are using with the flowmeter?  You should have a cal sheet that says what the output is.

Message Edited by Wayne.C on 04-16-2009 08:41 AM

[edholderman]

ok the help is great! thank you. I have it reading and made a custom scale. But now i am having a problem with it always reading 800mv when my pump is off. now i have to get it into an existing program. wow much fun

[Coq_Rouge]

The simplest thing is to create a frequency counter application. Most daq board do have counters. You will find all you need in the data sheet regarding converting pulses pr second from the flowmeter into gpm. This forum my help you with the frequency counting application. As a starter take a look at this http://zone.ni.com/devzone/cda/tut/p/id/7111 and read the "How to Make a Frequency Measurement" section

[EngineeringUnits]

thank you for your help