Yay! It looks like we're good to go on using the VTI pressure sensor. This does mean that we'll need to do our own calibration runs near vacuum, but that seems just fine.
Glenn, this means we're going to do some runs in Eric's vacuum chamber. Can you arrange this soon, like in about 2 weeks? Andrew -------- Original Message -------- Subject: Re: SCP1000 performance near a vacuum (< 30 kPa) Date: Wed, 21 Nov 2007 20:52:55 +0200 Hello Andrew, Here are some answers to you questions. 1. Output doesn't saturate to 30kPa value. In principle smallest value is zero (DATARD8 = 0x00 and DATARD16 = 0x0000). In practice there is some small offset value the output saturates. 2. Unfortunately I don't have much data to offer. We know that some customers have been tested SCP1000 down to 100Pa (and even lower) without problems and actually stated that output was quite linear. However they haven't share test results with us so I can't comment how linear it was. 3. Mechanical repeatability should be good so it should be possible to compensate/linearize output at low pressure. Hope this helps, Regards, Ville Nurmiainen Application Engineer VTI Technologies, Inc. Tel (313) 425 0850 Direct (313) 425 0849 Mobile (313) 641 0850 Fax (313) 425 0860 [EMAIL PROTECTED] >>> Andrew Greenberg <[EMAIL PROTECTED]> 20.11.2007 2:17 >>> Hello VTI, We're interested in using the VTI in an aerospace application that can reach large altitudes. However, there's no notes on what happens as the SCP1000 crosses the 30 kPa minimum range. Clearly the ~19 bits on the pressure sensor has the numeric range to go less than 30 kPa, so: 1. Does the pressure sensor just saturate at that numeric value? 2. Does the pressure output go non-linear at low pressures? 3. Even if it goes non-linear, might it be possible to linearize the low pressure performance given a calibration run and then some kind of curve fitting? Thanks so much, Andrew -- ------------------------------------------------------- Andrew Greenberg Portland State Aerospace Society (http://psas.pdx.edu/) [EMAIL PROTECTED] P: 503.788.1343 C: 503.708.7711 ------------------------------------------------------- -- ------------------------------------------------------- Andrew Greenberg Portland State Aerospace Society (http://psas.pdx.edu/) [EMAIL PROTECTED] P: 503.788.1343 C: 503.708.7711 ------------------------------------------------------- _______________________________________________ psas-avionics mailing list psas-avionics@lists.psas.pdx.edu http://lists.psas.pdx.edu/mailman/listinfo/psas-avionics
