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four flow meter with pulse outputs

counter

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#1 june0621

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Posted 11 May 2015 - 04:46 PM

I am the beginner with labjack and DAQ factory. 

 

Right now I got four flow meters which create pulse outputs. The result can be related to the total flow volume by a constant. I would like to use DaqFactory express with a U6 labjack to count and record the number of pulse over a set time period in order to determine the flow rate. The attached file is the detail of flow meter.

 

At the moment, I know there are two counters in U6. Wonder how is it possible to record outputs of four meters. 

 

Your input will be welcome.

 

Thank you!

Attached Files



#2 LabJack Support

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Posted 12 May 2015 - 06:54 AM

I see that the sensor has NPN output, which is good.  It will likely work with nothing extra, but for better resistance to external noise influences I recommend you add a 10k pull-up from each digital I/O line (FIOx/EIOx) to VS.

 

You can implement up to 6 counters on the U6 by using the 2 high-speed counters plus configuring the 4 timers as firmware counters:

 

http://labjack.com/s...users-guide/2.9

 

http://labjack.com/s...s-guide/2.9.1.5

 

Try it using the test panel in LJControlPanel first.  Once you see that it works in the test panel, go to "config defaults" and set and save the desired configuration as the power up default.  Then in DAQFactory you don't have to do any configuration, but rather can just read the timers or counters:

 

http://labjack.com/s...-app-guide/10.2



#3 june0621

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Posted 13 May 2015 - 02:57 PM

Thank you for the reply. Still got another simple problem. The K factor of flow meter is 1120. Is that means the actual flow rate is acquired by having counting outputs divided by this factor? 



#4 LabJack Support

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Posted 13 May 2015 - 03:05 PM

I did a quick search and K factor seems to be defined as pulses per unit volume, so if your k factor is 1120 pulses per cubic meter, then the following equation would seem true:

 

CM = NumPulses/1120





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