[time-nuts] OXCO insulation

Attila Kinali attila at kinali.ch
Wed Feb 25 04:16:58 EST 2015


On Tue, 24 Feb 2015 22:44:30 -0600
"Bill Hawkins" <bill at iaxs.net> wrote:

> One other thing to consider when designing an oven: put the temperature
> sensor
> as close as possible to the crystal. Distance delays the sensing of
> crystal temp,
> called dead time. Dead time will cause the controller to oscillate at
> lower gain,
> so the gain has to be reduced. This reduces the ability of the
> controller to
> respond to external temperature changes, called load disturbances.

Actually, you should put the temp sensor close to the heater, not the crystal.
The delay between the actuator (heater) and the feedback (temperature sensor)
defines the dead time. The presence of a crystal somewhere in the system is
of no importance to the oven controller, it's just additional thermal weight.


				Attila Kinali

-- 
It is upon moral qualities that a society is ultimately founded. All 
the prosperity and technological sophistication in the world is of no 
use without that foundation.
                 -- Miss Matheson, The Diamond Age, Neil Stephenson


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