Internal Plate Hold-down fixture

[Gianvito90]

thank you very much, you were very kind, I found these calculations on the internet, but I didn't understand what that constant was.....thank you very much...another question, if I change the internal orifice, how does the ECU know that should the value of C change? should it be set in the software settings?

[86rocco]

You're very welcome.
Without being familiar with the software you plan to use, I can't really answer that last question but somewhere in the data collection or post-processing software should be somewhere to enter flow characteristics of the orifice being used so that a cfm calculation can be made.
There is another way however and it's what was commonly done on old fashioned flow benches with inclined fluid manometers and that's to use a percentage scale. Determine what the maximum Δp of your differential pressure sensor is, I'll call that value Δpmax, then calibrate all of your orifices at Δpmax, then set up your software with a constant value of C=(100÷√Δpmax). Now the readings your software will give you is the percentage of the calibrated value of whatever orifice you're using, from there, calculating the cfm is just a very simple multiplication.

[Brucepts]

thank you very much, you were very kind, I found these calculations on the internet, but I didn't understand what that constant was.....thank you very much...another question, if I change the internal orifice, how does the ECU know that should the value of C change? should it be set in the software settings?

You will have to pass that info to the Arduino through a main program written in VB or some other language. Only other way would be to change the Arduino program variable each time you make configuration changes, compile and upload to the Arduino.

Suggest you start another thread in the public Flowbench DAQ area for further discussion

[Gianvito90]

Thanks so much everyone for the replies