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Message-ID: <54F9CC6C.7070903@ecosensory.com>
Date: Fri, 06 Mar 2015 09:49:00 -0600
From: John Griessen <john AT ecosensory DOT com>
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To: geda-user AT delorie DOT com
Subject: Re: [geda-user] [OT] Temperature sensor and control recommendation
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On 03/06/2015 08:55 AM, Evan Foss wrote:
> Why is everyone assuming this should be done digitally?

0.3 deg C is close to the tolerances of thermocouples you can buy,
and the temperature dependencies of the control circuit are
in that range also.  With so much needing calibration to get rid of offsets
and drifts, programmable seems the way to get whole-system accuracy.  Precision
is easy to get with digitizers and sigma delta tech, which leaves
accuracy of the whole system, and it's difficult and time consuming
to iterate the design of an analog machine exposed to fluctuating ambient
outside the oven, and sensor drift as it gets broken in with use over weeks.