Russ, mayf;
One data point that is easy to generate is to make up an ice water bath for
a zero degree (Celcius) calibration. In a beaker or glass jar, put in a big
handful of crushed ice and then add enough cold water to cover the ice. Stir
the whole thing constantly and after 5 minutes or so, drop the thermocouple
into the ice bath and allow it enough time to stabilize (when its temp
reading stops drifting). The key to getting a good calibration is to use
pure water (distilled is best) and do NOT stop stirring, especially when the
thermocouple is in the bath.
Regards, Neil Tucson, AZ
-----Original Message-----
From: Russel Mack [mailto:rtmack@concentric.net]
Sent: Tuesday, May 06, 2003 9:33 AM
To: DrMayf; Keith Turk; Nigel Shaw; land-speed@autox.team.net
Subject: RE: Quick Data Connectors
Mayf:
missed your point about starting the water cold, then boiling-- in my first
reply. Yeah, that would of course give you richer data-- although (during
the temperature increasing phase) you might have to make some "fudge-factor"
compensation for different temporal response of the two measurement devices.
(For example, a NIST-traceable RTD is often used for reference measurement,
and its time-response to temperature change is different from either of the
three common thermocouple constructions.) Russ, #1226B
-----Original Message-----
From: DrMayf [mailto:drmayf@teknett.com]
Sent: Wednesday, May 07, 2003 9:41 AM
To: Russel Mack; Keith Turk; Nigel Shaw; land-speed@autox.team.net
Subject: Re: Quick Data Connectors
Russ,
would it be satisfactory to "calibrate" the system by placing the probe in
first cold water, then boiling? With the daq on it sould give you the
correct results if all the inaccuracies you mention are absent or something
else entirely if screwed up. Like you, I have a very long history in the
test business and am skeptical of over the counter measurement systems that
are not calibrated or traceable to NBS in some form or fashion. My
experience comes from flight test of Boeing aircraft, Ballistic missiles
flight and ground test, scecret stuff at DOE in Oak Ridge, and lastly every
flipping part on the International Space Station that was manufactured by
Boeing or one of it subsidiaries.Bad data is dangerous. Not only do you need
to know the accuracy but also the resolition of the sensors and in fact the
complete system.
Anyhoo, nice chatting and I agree with you..
mayf
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