Dear Warren and Mark,
I have hacked together a very simple setup with the transistor circuit
and the opened Thunderbolt case (not its own case, but the front lid of
my outer case opened). The CPU fan was placed about 2 away, only
blowing indirectly into the case..
The results are simply
active PID temperature controller.
The more the mass, the slower the response, and the harder it can be for the
temperature loop to stabilizing.
ws
*
[time-nuts] Achievable temperature stability for Thunderbolt environment?
Achim Vollhardt avollhar at physik.uzh.ch
Tue Jan 18
Generally you have to do some playing with the fan position and internal
baffling and thermal mass for best performance of the temperature controller.
You don't want direct airflow onto the tbolt. Also you probably don't want an
large/aggressive fan... a little airflow can go a long way.
Looking at ways to optimize GPS-Rb-OCXO performance, using dewar, foam and
fan cooling, using a fan was an eye opener. I have now come to the
conclusion that for the temperature environment we are working in, a fan is
the
best way for all three. I am using a 5X5X1 cm fan drawing 50 mA at 12
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of ewkeh...@aol.com
Sent: Tuesday, January 18, 2011 9:12 AM
To: time-nuts@febo.com
Subject: Re: [time-nuts] Achievable temperature stability for Thunderbolt
Looking at ways to optimize GPS-Rb-OCXO
Hi
I see a degree or more over the weekend sitting on the bench. With some effort
that can be brought down to a half degree or so.
The real question is weather you see the signature of the temperature showing
up in the EFC plot. To be precise do you see the signature of the lab
temperature,
Dear Mark, Warren, Arnold,Bob and Charles,
Thank you all for the interesting responses. I am most interested about
the implemented temperature control in Lady Heather:
I see that there is a setpoint to be entered via 't'+'t', but I am
uncertain about the function of it. From the heather.cpp
Hi Achim,
I have very stable thermal conditions in my house. The temperature
indicated by the box (internal sensor) does stay stable within 50 mK/d
when the sun is not shining with very slow ripple. On sunny days the
in-box temperature does climb up by about 350 to 450 mK (less then 100
mK/h) and
Achim wrote:
I am just wondering, if I should rather worry more about high
temperature gradients rather than excursions from a mean value, as
slow variation can be compensated by the control loop while for
quick changes, the loop is just too slow :)
This has been discussed quite a bit on
Using Lady Heather's temperature controller (fan+cardboard box+solid state
relay+baffling and thermal mass to taste) I get around +/- 3 millidegree
temperature control when the AC/furnace is not running and +/- 20 millidegrees
with them cycling. Long term temperature average is down in the
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