[time-nuts] Temp/Humidity control systems?
phk at phk.freebsd.dk
Thu Oct 27 20:05:33 EDT 2016
In message <20161027134312.GA18158 at panix.com>, Ron Bean writes:
>And since this is time-nuts: Measuring humidity accurately is tricky.
>According to people who have tested them, commercial electronic humidity
>sensors, when tested in a lab, have never come anywhere close to the
>accuracy claimed in the data sheet.
The main problem in measuring humidity is physical gradients: It is
incredibly hard to create a volume of homogenous humidity on a planet
which has gravity, and for that reason, a lot of labs are not anywhere
near as accurate as they think they are.
>The exception is the "cold mirror" type of sensor, which measures the
>dewpoint by cooling a mirror and bouncing a light off it to sense the
>temperature where dew condenses on it. Those are expensive, and they
>require maintenance to keep the mirror clean.
And they are comparatively slow, last I saw one it could only do
a measurement every second minute.
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
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Never attribute to malice what can adequately be explained by incompetence.
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