please refer to
and
what is the difference between "Pressure Measurement type" absolute (MPX2102A) and the other type (MPX2102D)
if i use MPX2102A can i put Vout- to GND and read the output only from Vout+ ?
Absolute pressure sensors measure the pressure relative to an internal vacuum reference. So, it will be close to 100kPA with the port open at normal atmospheric pressure.
Differential type sensors measure the pressure on one port relative to that on another port. So, it will read close to 0 kPA with both ports open.
There are also sensors that have the second port non-customer-connectable and left open to the atmosphere (gauge pressure). They will also read close to 0kPA with the port open.
This is explained on page 2 of the data sheet.
No. Vout- is probably about half of the supply voltage. It's something like a Wheatstone bridge internally, probably with some extra elements for temperature compensation. You need a differential amplifier such as an instrumentation amplifier to use this kind of pressure sensor. There exist sensors with the circuitry built in, but of course they are more expensive.
Best regards, Spehro Pefhany
-- "it\'s the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
thanks,
and what about interfacing it with a PIC16f88 with 10bit AD converter with 2.048 vref, and 3.3V VCC supply ?
Shouldn't be any major problems. You'll need an amplifier, as I suggested.
Note that the output is ratiometric to the supply voltage for the sensor, so it may not make sense to use two references, as that may unnecessarily add two error terms. If you run the sensor from your
3.3V supply rather than the regulation 10V, you'll get 1/3 the output voltage (about 13mV F.S.), which is not too bad with high performance parts, given the 1%-ish accuracy of the part. Less self-heating as well.Best regards, Spehro Pefhany
-- "it\'s the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
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