On Tue, 22 Jul 2014 15:59:38 -0500
Bill Hawkins b...@iaxs.net wrote:
There is plenty of literature on the subject, but it is not in the scope
of precision time and frequency measurement.
I would like to disagree here. Precise time and frequency measurement
highly depends on precise control of
To ensure that steam is in a suitable state for temperature measurement
one uses a Hypsometer.
I made one out of tin cans and it sits on an electric hot plate.
It is not rocket science but it really works, my PT100 showed stable
temperatures within a
milliKelvin.
It is made so that the splash is
May I suggest thermistors and other temperature sensors made by Omega?
http://www.omega.com/pptst/44000_THERMIS_ELEMENTS.html
Their range of products is really large and prices are not too bad:
http://www.omega.com/temperature/tsc.html
take a look also to their literature:
For what it's worth:
One possible source is through GE Thermometrics. They used to be Just
Thermometrics bug GE bought them. The offer calibrated thermistors (At
leas they used to offer calibration), with AB and C vales stated.
Not sure what the costs are, but they make some pretty nice
Chuck Harris cfhar...@erols.com wrote:
Steam superheats only if the pressure is raised above standard pressure,
otherwise, steam at standard pressure will be exactly 212F, or 100C.
Saturated steam at standard pressure will be exactly 212F, or 100C.
Superheated steam is steam raised above the
- Original Message - From: Bill Dailey docdai...@gmail.com
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Sent: Monday, July 21, 2014 5:43 PM
Subject: Re: [time-nuts] temperature sensor
Ice water and boiling water coupled with altitude will give you two
points
On Tue, 22 Jul 2014 01:17:03 +0100
Brian D gro...@planet3.freeuk.co.uk wrote:
Saturated steam at standard pressure will be exactly 212F, or 100C.
Stupid question: How to you ensure that the steam is saturated,
while keeping a constant pressure?
I think just buying some indium off ebay and use
Group,
I worked for Rosemount, a manufacturer of precision resistance
thermometers, for many years.
Platinum does have a well-known formula for temperature versus
resistance, with second order corrections.
But a sensor is not enough. You need to convert its physical property to
a signal that is
In a container, as steam condenses the pressure will drop. The steam will stay
saturated. This is as long as the container contains steam only. Eventually,
as the steam cools and condenses you will be left with a vacuum contains only
minimal water vapor.
Sent from mobile
On Jul 22, 2014,
What I am missing in all these discussions is what do we want to archive
or is this an other paper only discussion. I am used to starting out with a
goal, and tackle the challenge from there.
We have a saying in German Papier ist geduldig. Translate You can write
any thing on paper.
On Sun, 20 Jul 2014 23:18:38 -0700
Tom Van Baak t...@leapsecond.com wrote:
To satisfy my curiosity and get actual data I'd like to place 6 or more
tiny analog high-resolution temperature sensors all around the OCXO of a
Trimble Thunderbolt. That's high-resolution both in temperature and in
NTC are not that very stable, they are amorphous material winch could
recrystallize slowly and therefore change it's electrical behavior ,
PT100 style is more reliable since it is pure metal
73
Alex
On 7/21/2014 1:22 AM, Attila Kinali wrote:
On Sun, 20 Jul 2014 23:18:38 -0700
Tom Van Baak
Hi Tom
I agre the educational aspect of time nuts is great and I have learned a
lot but it would be even more useful if discussions include what can be
attained and what may be in the reach of time nuts. I used to have a HP 2804A
with matched probe prom only used it once when developing a
Slow is not a problem in our applications the loop takes care of that. Will
look in to PT 100.
Bert Kehren
In a message dated 7/21/2014 8:19:48 A.M. Eastern Daylight Time,
alex...@ieee.org writes:
NTC are not that very stable, they are amorphous material winch could
recrystallize
On Mon, 21 Jul 2014 04:39:51 -0700
Alexander Pummer alex...@ieee.org wrote:
NTC are not that very stable, they are amorphous material winch could
recrystallize slowly and therefore change it's electrical behavior ,
PT100 style is more reliable since it is pure metal
How long is the time
Moin Bert,
On Mon, 21 Jul 2014 09:02:12 -0400 (EDT)
ewkeh...@aol.com wrote:
The challenge is reliable fan start at low voltage if you want the unit
stay constant over an ambient change of 10 C. Members have talked about u
processor control but I have not seen any thing that works, many of
Hello,
There are two types of NTC thermistors that are (very) frequently used
in spacecrafts, the Measurement Specialties (traditionally YSI, Yellow
Spring Instruments) 44907 and 44908, that are 10k @ 25ºC NTC:
http://meas-spec.com/downloads/44908.pdf and
I tried the
On Mon, Jul 21, 2014 at 7:02 AM, Attila Kinali att...@kinali.ch wrote:
How about doing it the old analog way? Feed the output of the
PID controller to comparator together with a sawtooth signal.
That will give you a quite nice 0-100% PWM control.
I'm quite sure a similar
You can find an interesting solution with the INA330. In the data sheet is
described a complete temperature PID controlled .
http://pdf.datasheetcatalog.com/datasheets/270/255641_DS.pdf
Luciano
www.timeok.it
On Mon 21/07/14 4:02 PM , Attila Kinali wrote:Moin Bert,
On Mon, 21 Jul 2014
Ice water and boiling water coupled with altitude will give you two points.
Sent from mobile
On Jul 21, 2014, at 10:12 AM, Attila Kinali att...@kinali.ch wrote:
On Mon, 21 Jul 2014 04:39:51 -0700
Alexander Pummer alex...@ieee.org wrote:
NTC are not that very stable, they are amorphous
I got a few of these
http://www.adafruit.com/products/374
to replace my TMP36. The idea was to get rid of the noise by using a
sensor with a built-in digital interface. They are spec'd for only 0.5C
accuracy but I think they are more repeatable and do much better than 0.5c
for relative
At 11:48 AM 7/21/2014, Chris Albertson wrote:
A better solution is to use a tachometer fan. Then the controller does not
set the fan voltage but sets the fan speed. there are still extra pins on
My thought exactly. I have not tried it, but it seems like this would
also automatically
DK1AG
-Ursprüngliche Nachricht-
Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag
von Attila Kinali
Gesendet: Samstag, 19. Juli 2014 13:46
An: Discussion of precise time and frequency measurement
Betreff: Re: [time-nuts] temperature sensor
On Wed, 25 Jun 2014 14
measurement
Betreff: Re: [time-nuts] temperature sensor
Hi
A temperature sensor crystal is very much the same thing as a normal
crystal (except for angle of cut). The mounting is pretty much the same as
the crystals you have seen before. The only thing you do to improve the
thermal coupling is to do
-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im
Auftrag von Attila Kinali
Gesendet: Sonntag, 20. Juli 2014 18:11
An: Tom Van Baak; Discussion of precise time and frequency measurement
Betreff: Re: [time-nuts] temperature sensor
Moin,
On Sun, 20 Jul 2014 07:55:23 -0700
Tom Van Baak t
docdai...@gmail.com said:
Ice water and boiling water coupled with altitude will give you two points.
Has anybody used a good thermometer to measure air pressure?
How much does the measured temperature vary between just barely boiling and a
good roiling boil? Or in various locations within
, 2014 5:43 PM
Subject: Re: [time-nuts] temperature sensor
Ice water and boiling water coupled with altitude will give you two
points.
Sent from mobile
On Jul 21, 2014, at 10:12 AM, Attila Kinali att...@kinali.ch wrote:
On Mon, 21 Jul 2014 04:39:51 -0700
Alexander Pummer alex...@ieee.org wrote
Hi:
A number of decades ago I wanted an easy way to get precision temperature
measurements when using HP Rocky Mountain Basic.
HP was selling thermistors specified to be accurate to 0.1 deg C when you interchanged thermistors. The readout can be
much more sensitive for applications like oven
5:43 PM
Subject: Re: [time-nuts] temperature sensor
Ice water and boiling water coupled with altitude will give you two points.
Sent from mobile
On Jul 21, 2014, at 10:12 AM, Attila Kinali att...@kinali.ch wrote:
On Mon, 21 Jul 2014 04:39:51 -0700
Alexander Pummer alex...@ieee.org wrote
On 7/21/2014 11:36 AM, Hal Murray wrote:
docdai...@gmail.com said:
Ice water and boiling water coupled with altitude will give you two points.
Has anybody used a good thermometer to measure air pressure?
How much does the measured temperature vary between just barely boiling and a
good
, July 21, 2014 9:11 PM
Subject: Re: [time-nuts] temperature sensor
Hi:
The temperature of steam can be anything above boiling water.
http://en.wikipedia.org/wiki/Steam
Super heating of steam was common railroad practice.
Boiling pure water will get rid of any trapped gases quickly.
In fact
Steam superheats only if the pressure is raised above standard pressure,
otherwise, steam at standard pressure will be exactly 212F, or 100C.
-Chuck Harris
Brooke Clarke wrote:
Hi:
The temperature of steam can be anything above boiling water.
http://en.wikipedia.org/wiki/Steam
Super heating
Hi
If you look at the people running very precise thermometers (sub 0.001C) they
are doing better with thermistors than with PRT’s. Both the PRT’s and the
thermistors come with notes on them requiring on location re-certification
below he 0.01C level. A triple point of water cell is typically
On Mon, 21 Jul 2014 18:00:59 -0400
Chuck Harris cfhar...@erols.com wrote:
Steam superheats only if the pressure is raised above standard pressure,
otherwise, steam at standard pressure will be exactly 212F, or 100C.
Uhm.. you are the second one claiming this. Could you please explain
what
Tom wrote:
There have been several discussions over the years about variable
fan speed based temperature control. I can't explain it, but I've
always been suspicious of this technique. It seems to me still air
is inherently better than moving air. Passive (no fan) is better
than active
Thank you Charles
. As a first step I will fill one of my Tbolt boxes with small foam
particles. Sounds like a good idea. I have one unit where I have given
particular
attention to low power from the power supply.
Bert Kehren
In a message dated 7/21/2014 7:43:49 P.M. Eastern Daylight
Hi,
as a bit of a temperature nut, here are some observations.
Diodes work as temperature sensors, but better is the trans-diode,
a bipolar transistor with collector connected to base. Sensitivity
about 2.2 mV/K, I did not use them much in spite of their linearity
and low cost.
PT100 is only
One cheap device that has a fairly predictable tempco over a fairly good
range of temperatures is the lowly ceramic resonator - especially the
low frequency variety (e.g. 400-500 kHz) having a reasonably straight
line temperature versus frequency curve. If one already has a decent
frequency
To satisfy my curiosity and get actual data I'd like to place 6 or more
tiny analog high-resolution temperature sensors all around the OCXO of a
Trimble Thunderbolt. That's high-resolution both in temperature and in time.
In other words, no fake accuracy averaging allowed. The goal is to
You don't use ice as a reference. With ice water, the same principles apply
that apply to boiling water. This is why these are convenient calibration
check points.
Sent from mobile
On Jul 21, 2014, at 3:51 PM, jim s jwsm...@jwsss.com wrote:
On 7/21/2014 11:36 AM, Hal Murray wrote:
: [time-nuts] temperature sensor
Ice water and boiling water coupled with altitude will give you two
points.
Sent from mobile
On Jul 21, 2014, at 10:12 AM, Attila Kinali att...@kinali.ch wrote:
On Mon, 21 Jul 2014 04:39:51 -0700
Alexander Pummer alex...@ieee.org wrote:
NTC
Hi
If you want to hit 1 mK with your home made triple point cell, you will need a
source of very clean water and some luck with materials and cleaning processes.
If you want to go below that level, you will need an isotope readout on your
water source. Rain water, and mid-continent well water
That is a great idea. Thank you.
I can see use for this on more then one project. I have some really
poor preforming traction motors on a small robot. This is one of
those flap your forehead why did I not think of something so simple?
events. I'll call it a kick starter
BTW, one project,
You don't want to do freezing point tests with gallium... it really likes to
supercool without freezing. A gallium triple point cell is the way to go.
Good reading here: http://www.nist.gov/calibrations/upload/met15-79.pdf
I once built some precision temperature measurement equipment that we
Absolutely nothing limits the temperature of steam in
air. It can easily be superheated to thousands of degrees F.
However, at the water/steam interface, the steam will be
exactly 100C at standard pressure as it vaporizes. Even if the
water is full of dissolved matter, and has a slightly
On Mon, Jul 21, 2014 at 5:54 PM, Bill Dailey docdai...@gmail.com wrote:
You don't use ice as a reference. With ice water, the same principles apply
that apply to boiling water. This is why these are convenient calibration
check points.
How much does the measured temperature vary between
The maximum temperature of saturated steam temperature depends on
pressure; unsaturated steam does not. At work, we just finished a
project using steam at over 800F to drive a jet mill.
Brent
http://en.wikipedia.org/wiki/Superheated_steam
On 7/21/2014 5:39 PM, Attila Kinali wrote:
On Mon,
Message: 4
Date: Mon, 21 Jul 2014 19:50:07 -0400 (EDT)
From: ewkeh...@aol.com
. As a first step I will fill one of my Tbolt boxes with small foam
particles. Sounds like a good idea.
Sounds like an invitation to ESD damage. Maybe dissipative foam.
--
Chris Caudle
Hi Alex,
Thanks for this level of detail. Fascinating. Is the fundamental physics behind
the quartz angle-of-cut well understood, or does this fall into advanced
alchemy and industrial magic?
I understand about the time constant now. Yes, on the order of a few seconds
makes sense. Would it be
Moin,
On Sun, 20 Jul 2014 07:55:23 -0700
Tom Van Baak t...@leapsecond.com wrote:
Thanks for this level of detail. Fascinating. Is the fundamental physics
behind the quartz angle-of-cut well understood, or does this fall into
advanced alchemy and industrial magic?
From what i gathered from my
1) Axtal makes a direct temperature sensing crystal, see Bern Neubig's
former note, but since I grew up by learning how do you make one iron
wheel from wood, I tried and used the transistor PN junction method many
times, it works and it is not a which craft to calculate the tree
resistors for
A long time ago in one of my excursions into medical electronics,
I was involved in developing a microwave hyperthermia cancer treatment
system that used a quartz thermometry unit to sense the tumor temperatures.
The quartz thermometry unit had optical fibers with quartz crystals (about
the size
On Sun, 20 Jul 2014 15:57:24 -0400
Chuck Harris cfhar...@erols.com wrote:
I initially thought that it might be a transmission sort of effect, where
the light intensity changed with temperature, but its total lack of
sensitivity
to being in a liquid, kind of makes that unlikely.
Nope, it's a
What I am missing in all these discussions is what do we want to archive
or is this an other paper only discussion. I am used to starting out with a
goal, and tackle the challenge from there.
We have a saying in German Papier ist geduldig. Translate You can write
any thing on paper.
Bert
That sounds sort of like what they must have been doing.
But, they were quite clear that it was a Quartz thermometry
unit, and that the crystals were quartz.
And, this was before solid state IR laser diodes, around 1982.
Each temperature measuring module was plug in, and about 3/4 inch
by 5
On Wed, 25 Jun 2014 14:21:49 +0200
Bernd Neubig bneu...@t-online.de wrote:
the time-nut approach for temperature measurement would be to use
a temperature sensor crystal - like the good old Hewlett-Packard guys
did many years ago. If you do not look for ultra-linearity of the frequency
vs.
Hi
A “temperature sensor crystal” is very much the same thing as a normal crystal
(except for angle of cut). The mounting is pretty much the same as the crystals
you have seen before. The only thing you do to improve the thermal coupling is
to do a backfill with something like helium. Backfill
:12
An: Discussion of precise time and frequency measurement
Betreff: Re: [time-nuts] temperature sensor
After having tried just about every solution under the sun, my opinion is that
within the ambient temperature range (up to at least 100°C) and homebrew
budgets, nothing beats an NTC thermistor
After having tried just about every solution under the sun, my opinion is that
within the ambient temperature range (up to at least 100°C) and homebrew
budgets, nothing beats an NTC thermistor.
They are inexpensive, have a large output and interface most easily with a
microcontroller's ADC in
We use NTC 10K with the FRK. Precision is not important.We have to play
with the settings in order to have fan starting voltage over the full temp.
range.
Bert Kehren
In a message dated 6/24/2014 8:12:45 P.M. Eastern Daylight Time,
shali...@gmail.com writes:
After having tried just
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