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Regarding pressure ratios -
http://www.omega.com/pptst/HHP886.html
That's a handheld dual port manometer that can show and record both IM and EM pressures as well as the delta.
Are there better options out there? What data log system might this integrate with?
It would be nice to see pressure ratio dynamically, at different power points.
Only 2psi differential. ..
I would think you would need a greater range for the purpose you specified.
This instrument would be better served measuring a different across a filter, other similar small pressure difference.
Yes, good points. I called them and got this recommendation for the application -
http://www.omega.com/pptst/HHP4200.html#order
There is a sub-model - HHP4230 - with a 30 PSI range. and the HHP4215 with a 15 PSI range.
Looks like it would work, but I'd advise getting the 0-100PSI model, it still has resolution to one tenth of a PSI and a "Proof" pressure of 150, overall a more robust unit, so it will take more abuse.
There is optional software for the RS232 port, but I imagine Wozer or another electronic wiz could figure how to tease the data out of the unit via that cable.
The only thing that I don't like about the unit is the response time of .5sec. If that's just a delay and not sample frequency, it'll be fine. As a good friend of mine explained, an error that is consistent is manageable/compensatable.
In reality, the delay is probably more effected by the size/length of the tubing used, to that end, you'll want to have both sides of the unit use the same length tubing so they "see" things the same/in sync.
Even the price isn't too bad!
Looks like the tubing is common size and will work with push-lock connectors, both available from McMaster Car...
Mike
off topic so i'll only post once but i would think a couple $20 0-100 psi 5v transducers plugged into the mpscilink board would work well. the sampling rate would be in the 2-4 mSec range, so possibly hundreds of samples per second as an extreme.
Agreed in addition one can purchase one with two ports that is designed for differential measurements.Quote:
Originally Posted by wowzer
WRT, tube size and delay time for pressure. We measure like this all the time at my work, as my physics colleagues explain the pressure is transmitted as a wave that travels at the speed of sound down the tube. Here is a physics link to help explain the process.
https://physics.stackexchange.com/qu...side-of-a-tube
You can also think about a water hammer in your water pipes at home and how quickly it transmits throughout the whole house.
Differential, 72psi range, 5V out, 5V power
Pressure cant reverse direction though..so P1 > P2 always
$11.09 at single quantity, digikey
http://cache.freescale.com/files/sen...et/MPX5500.pdf
Digikey has tens of thousands of pressure sensors, try their search engine. Maybe find one thats better. Ebay too.
We use the Freescale at work and they work quite well. For over 25 years I have used these without failure.Quote:
Originally Posted by acannell