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| Author |
Cheap thermometer calibration technique?
|
|
|
| I know this subject of "cheap" and "calibrate" used in the same sentence may
well be anathema to some of you but I need to verify that either my IR temp
gun is accurate or my DMM/thermocouple is, or neither. Accuracy to 2 or 3
degrees F is fine.
I'm looking for suggestions for a simple way to provide some kind of common
temperature "standard" (I use the term loosely, here) I can compare these
against.
Thanks,
--
DaveC
me@bogusdomain.net
This is an invalid return address
Please reply in the news group
| |
| MooseFET 2007-05-08, 1:25 pm |
| On May 8, 7:56 am, DaveC <m...@privacy.net> wrote:
> I know this subject of "cheap" and "calibrate" used in the same sentence may
> well be anathema to some of you but I need to verify that either my IR temp
> gun is accurate or my DMM/thermocouple is, or neither. Accuracy to 2 or 3
> degrees F is fine.
>
> I'm looking for suggestions for a simple way to provide some kind of common
> temperature "standard" (I use the term loosely, here) I can compare these
> against.
The freezing/melting point of ice is quite exact. Boiling water is
good if you correct for your local air pressure.
| |
| John Larkin 2007-05-08, 1:25 pm |
| On Tue, 08 May 2007 14:56:50 GMT, DaveC <me@privacy.net> wrote:
>I know this subject of "cheap" and "calibrate" used in the same sentence may
>well be anathema to some of you but I need to verify that either my IR temp
>gun is accurate or my DMM/thermocouple is, or neither. Accuracy to 2 or 3
>degrees F is fine.
>
>I'm looking for suggestions for a simple way to provide some kind of common
>temperature "standard" (I use the term loosely, here) I can compare these
>against.
>
>Thanks,
Freezing and boiling water are obvious points.
Tapwater stirred with a lot of crushed ice will get within 10-15 mK of
0 deg C. Boiling water, corrected for barometric pressure, will get
within your error budget.
You can buy a thinfilm platinum RTD, for a few dollars, that is
accurate to a fraction of a deg C, if you measure it with a good
ohmmeter. Some of the semiconductor temp sensors are better than 1 deg
C.
Fever thermometers are very good close to body temp. That and ice
point is a combination that's hard to beat.
John
| |
|
| In article <0001HW.C265DDC10131FF4EF01826C8@news.sf.sbcglobal.net>, me@privacy.net wrote:
>I know this subject of "cheap" and "calibrate" used in the same sentence may
>well be anathema to some of you but I need to verify that either my IR temp
>gun is accurate or my DMM/thermocouple is, or neither. Accuracy to 2 or 3
>degrees F is fine.
>
>I'm looking for suggestions for a simple way to provide some kind of common
>temperature "standard" (I use the term loosely, here) I can compare these
>against.
I don't think i have boiled any water or iced a thermometer lately. I try to
check out an unknown by a known in the shop. Sometimes I may have to use a third
or fourth device to be sure. That is a problem to contend with, its very difficult to place more
than one probe in one spot. I try to test using a beaker of water being stirred very rapidly,
otherwise temperature differential will kill you. Measuring IR can be trickey, as I found out
at home measuring aluminum foil. The heat of the reflection is what you will measure.
Since I have a few thermometers on the wall at home. viewing the IR probe vs the readout
gives a feel for the accuracies involved.
greg
| |
|
| John Larkin wrote:
> On Tue, 08 May 2007 14:56:50 GMT, DaveC <me@privacy.net> wrote:
>
>
> Freezing and boiling water are obvious points.
>
> Tapwater stirred with a lot of crushed ice will get within 10-15 mK of
> 0 deg C. Boiling water, corrected for barometric pressure, will get
> within your error budget.
>
> You can buy a thinfilm platinum RTD, for a few dollars, that is
> accurate to a fraction of a deg C, if you measure it with a good
> ohmmeter. Some of the semiconductor temp sensors are better than 1 deg
> C.
>
> Fever thermometers are very good close to body temp. That and ice
> point is a combination that's hard to beat.
>
> John
>
>
>
Don't forget that with your IR gun, the
emissivity of the source is important in
calibration. I suspect water and ice are
not friendly calibration sources. Maybe
a black anodized heat sink that has been
heated to some calibrated temperature
would be a good source. Does your gun
have an emissivity adjustment?
Chuck
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| |
| Spehro Pefhany 2007-05-08, 1:25 pm |
| On Tue, 08 May 2007 14:56:50 GMT, the renowned DaveC <me@privacy.net>
wrote:
>I know this subject of "cheap" and "calibrate" used in the same sentence may
>well be anathema to some of you but I need to verify that either my IR temp
>gun is accurate or my DMM/thermocouple is, or neither. Accuracy to 2 or 3
>degrees F is fine.
>
>I'm looking for suggestions for a simple way to provide some kind of common
>temperature "standard" (I use the term loosely, here) I can compare these
>against.
>
>Thanks,
At what temperature? You have to consider emissivity with IR
measurements. If your DMM/thermocouple reads okay with the input
shorted (terminal block temperature) chances are it's accurate enough
at typical heat sink temperatures. Chances are your IR is not.
Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
| |
| John Larkin 2007-05-08, 1:25 pm |
| On Tue, 08 May 2007 15:35:34 GMT, szekeres@pitt.edu (GregS) wrote:
>In article <0001HW.C265DDC10131FF4EF01826C8@news.sf.sbcglobal.net>, me@privacy.net wrote:
>
>I don't think i have boiled any water or iced a thermometer lately. I try to
>check out an unknown by a known in the shop. Sometimes I may have to use a third
>or fourth device to be sure. That is a problem to contend with, its very difficult to place more
>than one probe in one spot. I try to test using a beaker of water being stirred very rapidly,
>otherwise temperature differential will kill you. Measuring IR can be trickey, as I found out
>at home measuring aluminum foil. The heat of the reflection is what you will measure.
If you IR measure shiny copper or brass, what you're measuring is your
own reflection.
I dab things with black whiteboard marker to improve the emissivity.
Apparently Scotch Magic tape has high emissivity, too.
John
| |
| RST Engineering \(jw\) 2007-05-08, 1:25 pm |
| Ice mixed with distilled (or for your purposes, tap will be fine) water and
allowed to rest for a few minutes will give you 32°F within millidegrees.
Be sure to stir it every half minute or so to get the thermoclines well
distributed.
Boiling water at sea level will give you 212°F fairly accurately, less 1°F
(for your stated accuracy) for every thousand feet of altitude you are above
sea level up to a few thousand feet.
Jim
"DaveC" <me@privacy.net> wrote in message
news:0001HW.C265DDC10131FF4EF01826C8@news.sf.sbcglobal.net...
>I know this subject of "cheap" and "calibrate" used in the same sentence
>may
> well be anathema to some of you but I need to verify that either my IR
> temp
> gun is accurate or my DMM/thermocouple is, or neither. Accuracy to 2 or 3
> degrees F is fine.
>
> I'm looking for suggestions for a simple way to provide some kind of
> common
> temperature "standard" (I use the term loosely, here) I can compare these
> against.
>
> Thanks,
> --
> DaveC
> me@bogusdomain.net
> This is an invalid return address
> Please reply in the news group
>
| |
| John O'Flaherty 2007-05-08, 1:25 pm |
| On May 8, 8:56 am, DaveC <m...@privacy.net> wrote:
> I know this subject of "cheap" and "calibrate" used in the same sentence may
> well be anathema to some of you but I need to verify that either my IR temp
> gun is accurate or my DMM/thermocouple is, or neither. Accuracy to 2 or 3
> degrees F is fine.
>
> I'm looking for suggestions for a simple way to provide some kind of common
> temperature "standard" (I use the term loosely, here) I can compare these
> against.
Not sure what you mean by "cheap", but you can get a YSI thermilinear
network, which consists of a composite of three thermistors and some
precision resistors for about $27. The one that goes from 0-100C
claims +/- 0.15C accuracy (+/- 0.27F).
That might be expensive for one calibration, but you might use it in
the future.
Then, you could get a black anodized heat sink with one side smooth,
and drill little holes in the side, close to the flat surface, and
insert the YSI thermistor and your thermocouple, maybe with some heat
sink glop. Then point the IR detector at it. Let it go through some
temperature changes slow enough that the whole thing has time to
equlibrate, and collect some calibration data for both devices.
--
John
| |
| Spehro Pefhany 2007-05-08, 1:25 pm |
| On Tue, 8 May 2007 09:10:23 -0700, the renowned "RST Engineering
\(jw\)" <jim@rstengineering.com> wrote:
>Ice mixed with distilled (or for your purposes, tap will be fine) water and
>allowed to rest for a few minutes will give you 32°F within millidegrees.
>Be sure to stir it every half minute or so to get the thermoclines well
>distributed.
>
>Boiling water at sea level will give you 212°F fairly accurately, less 1°F
>(for your stated accuracy) for every thousand feet of altitude you are above
>sea level up to a few thousand feet.
>
>Jim
It's possible to get a couple of degrees F error (high) from boiling
water, particularly if you use a smooth vessel, such as a glass
beaker, to boil the water. Maybe put something like an airstone in the
bottom of the vessel.
Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
| |
|
| > At what temperature?
~130F, max. I am frequently asked to measure the temp of a stack of press
output (big 6-color sheet-fed presses) to determine if the IR dryer lamps are
functioning properly. Sometimes using an IR gun is fine, but some press
operators prefer the traditional method of a probe inserted halfway down the
stack. It would be nice if my tools' readings corresponded.
Re. the ice "calibration": as someone pointed out, ice & h2o isn't very
IR-emissive, it it? Would it help to mix in a little black ink? (Lots lying
around a print shop...)
Thanks,
--
DaveC
me@bogusdomain.net
This is an invalid return address
Please reply in the news group
| |
| Spehro Pefhany 2007-05-08, 1:25 pm |
| On Tue, 08 May 2007 17:15:53 GMT, the renowned DaveC <me@privacy.net>
wrote:
>
>~130F, max. I am frequently asked to measure the temp of a stack of press
>output (big 6-color sheet-fed presses) to determine if the IR dryer lamps are
>functioning properly. Sometimes using an IR gun is fine, but some press
>operators prefer the traditional method of a probe inserted halfway down the
>stack. It would be nice if my tools' readings corresponded.
All that IR from the lamps might be reflecting around and giving you
problems too.
>Re. the ice "calibration": as someone pointed out, ice & h2o isn't very
>IR-emissive, it it? Would it help to mix in a little black ink? (Lots lying
>around a print shop...)
It won't mix in (it's oily), that's kinda the point with offset
printing. ;-)
>Thanks,
Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
| |
| Rich Grise 2007-05-08, 1:25 pm |
| On Tue, 08 May 2007 08:44:00 -0700, John Larkin wrote:
> On Tue, 08 May 2007 15:35:34 GMT, szekeres@pitt.edu (GregS) wrote:
>
> If you IR measure shiny copper or brass, what you're measuring is your
> own reflection.
>
> I dab things with black whiteboard marker to improve the emissivity.
> Apparently Scotch Magic tape has high emissivity, too.
I once used cigarette ashes and spit on a piece of aluminum. :-)
Cheers!
Rich
| |
| Rich Grise 2007-05-08, 1:25 pm |
| On Tue, 08 May 2007 17:15:53 +0000, DaveC wrote:
>
> ~130F, max. I am frequently asked to measure the temp of a stack of press
> output (big 6-color sheet-fed presses) to determine if the IR dryer lamps are
> functioning properly. Sometimes using an IR gun is fine, but some press
> operators prefer the traditional method of a probe inserted halfway down the
> stack. It would be nice if my tools' readings corresponded.
>
> Re. the ice "calibration": as someone pointed out, ice & h2o isn't very
> IR-emissive, it it? Would it help to mix in a little black ink? (Lots lying
> around a print shop...)
>
Can you take the probe and the IR out to the line simultaneously and check
a pile of paper with both of them simultaneously? You'd need the
cooperation of the foreman and the workers, of course.
Good Luck!
Rich
| |
|
| > All that IR from the lamps might be reflecting around and giving you
> problems too.
Measurement is taken after printing is done and lamps are cooled (they aren't
in direct "sight" of the delivery stack on the press, anyway).
> It won't mix in (it's oily), that's kinda the point with offset
> printing. ;-)
We've got lots of (large format) inkjet printers, too! Would h2o-soluble ink
in the ice water increase the emissivity?
--
DaveC
me@bogusdomain.net
This is an invalid return address
Please reply in the news group
| |
|
| > Can you take the probe and the IR out to the line simultaneously and check
> a pile of paper with both of them simultaneously?
So where's the "standard" in this experiment?
--
DaveC
me@bogusdomain.net
This is an invalid return address
Please reply in the news group
| |
| Spehro Pefhany 2007-05-08, 5:25 pm |
| On Tue, 08 May 2007 18:24:09 GMT, the renowned DaveC <me@privacy.net>
wrote:
>
>Measurement is taken after printing is done and lamps are cooled (they aren't
>in direct "sight" of the delivery stack on the press, anyway).
>
>
>We've got lots of (large format) inkjet printers, too! Would h2o-soluble ink
>in the ice water increase the emissivity?
Yes, but I don't know how you're going to get a matt finish on the
water. More importantly perhaps, the ink might alter the boiling
point.
Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
| |
| John Larkin 2007-05-08, 5:25 pm |
| On Tue, 08 May 2007 17:15:53 GMT, DaveC <me@privacy.net> wrote:
>
>~130F, max. I am frequently asked to measure the temp of a stack of press
>output (big 6-color sheet-fed presses) to determine if the IR dryer lamps are
>functioning properly. Sometimes using an IR gun is fine, but some press
>operators prefer the traditional method of a probe inserted halfway down the
>stack. It would be nice if my tools' readings corresponded.
>
>Re. the ice "calibration": as someone pointed out, ice & h2o isn't very
>IR-emissive, it it? Would it help to mix in a little black ink? (Lots lying
>around a print shop...)
>
>Thanks,
If you use a stainless thermos or Starbucks coffee mug thing, and fill
it with stirred crushed ice and water, and fire an ir sensor down into
that, it should be pretty good.
I've got an ice cube on a paper plate on my desk, just starting to
melt. Our FLIR thermal imager shows it at about +0.5C, and a cheap
Extech IR thermometer claims -2C.
The emissivity of the ice cube seems close to 1.0. As I image it and
wave my hand around nearby, there's no hint of thermal reflections or
temperature change, so it's almost totally black in the thermal IR.
Oh my red plastic Presidential Water Cup is on my desk, too, with
about an inch of water in the bottom. It reads 6.8C with a
thermocouple, 7.0 on the FLIR, and 4C on the Extech. Again, no hint of
reflections. So water also looks black at thermal wavelengths.
John
| |
| Tim Wescott 2007-05-08, 5:25 pm |
| John Larkin wrote:
> On Tue, 08 May 2007 17:15:53 GMT, DaveC <me@privacy.net> wrote:
>
>
> If you use a stainless thermos or Starbucks coffee mug thing, and fill
> it with stirred crushed ice and water, and fire an ir sensor down into
> that, it should be pretty good.
>
> I've got an ice cube on a paper plate on my desk, just starting to
> melt. Our FLIR thermal imager shows it at about +0.5C, and a cheap
> Extech IR thermometer claims -2C.
>
> The emissivity of the ice cube seems close to 1.0. As I image it and
> wave my hand around nearby, there's no hint of thermal reflections or
> temperature change, so it's almost totally black in the thermal IR.
>
> Oh my red plastic Presidential Water Cup is on my desk, too, with
> about an inch of water in the bottom. It reads 6.8C with a
> thermocouple, 7.0 on the FLIR, and 4C on the Extech. Again, no hint of
> reflections. So water also looks black at thermal wavelengths.
>
> John
>
Is your FLIR imager one of the cryo-cooled ones, or do you have a newer
one (less than a decade old) with the uncooled detector?
--
Tim Wescott
Wescott Design Services
http://www.wescottdesign.com
Posting from Google? See http://cfaj.freeshell.org/google/
Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html
| |
| RST Engineering \(jw\) 2007-05-08, 5:25 pm |
| Talk about measuring with a micrometer, marking with chalk, and cutting with
an axe!!!
The fellow is looking for a couple of °F accuracy.
Jim
"John O'Flaherty" <quiasmox@yahoo.com> wrote in message
news:1178640978.897320.267180@e65g2000hsc.googlegroups.com...
>
> Not sure what you mean by "cheap", but you can get a YSI thermilinear
> network, which consists of a composite of three thermistors and some
> precision resistors for about $27. The one that goes from 0-100C
> claims +/- 0.15C accuracy (+/- 0.27F).
> That might be expensive for one calibration, but you might use it in
> the future.
> Then, you could get a black anodized heat sink with one side smooth,
> and drill little holes in the side, close to the flat surface, and
> insert the YSI thermistor and your thermocouple, maybe with some heat
> sink glop. Then point the IR detector at it. Let it go through some
> temperature changes slow enough that the whole thing has time to
> equlibrate, and collect some calibration data for both devices.
> --
> John
>
| |
| John Larkin 2007-05-08, 5:25 pm |
| On Tue, 08 May 2007 12:37:07 -0700, Tim Wescott <tim@seemywebsite.com>
wrote:
>John Larkin wrote:
>Is your FLIR imager one of the cryo-cooled ones, or do you have a newer
>one (less than a decade old) with the uncooled detector?
It's an E45, about a year old, uncooled. About every 30 seconds, it
clicks and seems to close an internal shutter for a couple of seconds,
which I assume is some sort of auto-cal of the sensor array.
It's pretty slick, except for the USB interface which is bizarre. It's
a network device, not memory like other cameras, and you have to
install their strange software to talk to it.
We can focus so close that we can image the hot-spot temp on an 0603
resistor! Imaging an operating pcb can lead to all sorts of
revelations.
We looked at the Fluke, but nobody at Fluke seemed to understand it.
Not a good sign.
John
| |
| John Larkin 2007-05-08, 5:25 pm |
| On Tue, 08 May 2007 12:20:02 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>On Tue, 08 May 2007 17:15:53 GMT, DaveC <me@privacy.net> wrote:
>
>
>If you use a stainless thermos or Starbucks coffee mug thing, and fill
>it with stirred crushed ice and water, and fire an ir sensor down into
>that, it should be pretty good.
>
>I've got an ice cube on a paper plate on my desk, just starting to
>melt. Our FLIR thermal imager shows it at about +0.5C, and a cheap
>Extech IR thermometer claims -2C.
>
>The emissivity of the ice cube seems close to 1.0. As I image it and
>wave my hand around nearby, there's no hint of thermal reflections or
>temperature change, so it's almost totally black in the thermal IR.
>
>Oh my red plastic Presidential Water Cup is on my desk, too, with
>about an inch of water in the bottom. It reads 6.8C with a
>thermocouple, 7.0 on the FLIR, and 4C on the Extech. Again, no hint of
>reflections. So water also looks black at thermal wavelengths.
>
>John
My FLIR rep confirms: water is 0.98.
John
| |
| Tim Wescott 2007-05-08, 5:25 pm |
| John Larkin wrote:
> On Tue, 08 May 2007 12:37:07 -0700, Tim Wescott <tim@seemywebsite.com>
> wrote:
>
>
> It's an E45, about a year old, uncooled. About every 30 seconds, it
> clicks and seems to close an internal shutter for a couple of seconds,
> which I assume is some sort of auto-cal of the sensor array.
>
> It's pretty slick, except for the USB interface which is bizarre. It's
> a network device, not memory like other cameras, and you have to
> install their strange software to talk to it.
>
> We can focus so close that we can image the hot-spot temp on an 0603
> resistor! Imaging an operating pcb can lead to all sorts of
> revelations.
>
> We looked at the Fluke, but nobody at Fluke seemed to understand it.
> Not a good sign.
>
> John
>
The internal shutter is for NUC (Non-Uniform Correction) -- focal plane
array sensors in general (even visible light) have gain and offset
differences from one pixel to the next. Part of it is periodic with the
internal structure of the chip or with polish marks. The rest is just
purely random. Visible light sensors can be selected to eliminate this
to some extent (pro video cameras have nonuniformity correction, but the
camera manufacturers won't admit it). IR detectors can't, and the
amount of nonuniformity in the uncooled detectors can be astonishing; as
of five years ago it could be 100x as much as your intended signal.
So every once in a while the shutter comes down, the internal logic
recalibrates the NUC, and the camera continues on.
There are only a few companies that actually manufacture imagers (FLIR
Sweden is one). So many companies that "make" IR imagers are just
plopping an OEM module made by someone else into their case.
--
Tim Wescott
Wescott Design Services
http://www.wescottdesign.com
Posting from Google? See http://cfaj.freeshell.org/google/
Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html
| |
| The Great Attractor 2007-05-08, 8:25 pm |
| On Tue, 08 May 2007 14:56:50 GMT, DaveC <me@privacy.net> wrote:
>I know this subject of "cheap" and "calibrate" used in the same sentence may
>well be anathema to some of you but I need to verify that either my IR temp
>gun is accurate or my DMM/thermocouple is, or neither. Accuracy to 2 or 3
>degrees F is fine.
>
>I'm looking for suggestions for a simple way to provide some kind of common
>temperature "standard" (I use the term loosely, here) I can compare these
>against.
>
>Thanks,
Doesn't 63/37 solder melt at 485° F at sea level?
That would calibrate the thermocouple.
The IR is a bit trickier as the surfaces you examine have differing
emissivities.
You likely have a calibrated instrument, but forget to shift for
emissivity differences.
For the IR to cal correctly, you need a "black body calibration source,
which is typically an Aluminum ingot painted with IR paint.
You can learn a lot here:
http://www.mikroninfrared.com/App_N...iples_of_IR.pdf
These guys are the tops.
| |
| The Great Attractor 2007-05-08, 8:25 pm |
| On 8 May 2007 08:14:10 -0700, MooseFET <kensmith@rahul.net> wrote:
>On May 8, 7:56 am, DaveC <m...@privacy.net> wrote:
>
>The freezing/melting point of ice is quite exact. Boiling water is
>good if you correct for your local air pressure.
>
Freezing point and melting point are also pressure related, and so they
too vary.
Also, water has a very low emissivity, and would be a very poor choice
for a reading on the IR instrument.
| |
| The Great Attractor 2007-05-08, 8:25 pm |
| On Tue, 08 May 2007 08:15:21 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>On Tue, 08 May 2007 14:56:50 GMT, DaveC <me@privacy.net> wrote:
>
>
>Freezing and boiling water are obvious points.
>
>Tapwater stirred with a lot of crushed ice will get within 10-15 mK of
>0 deg C. Boiling water, corrected for barometric pressure, will get
>within your error budget.
>
>You can buy a thinfilm platinum RTD, for a few dollars, that is
>accurate to a fraction of a deg C, if you measure it with a good
>ohmmeter. Some of the semiconductor temp sensors are better than 1 deg
>C.
>
>Fever thermometers are very good close to body temp. That and ice
>point is a combination that's hard to beat.
>
>John
>
For his thermocouple. Not good choices for the IR device, however.
The body temp thermometer is VERY accurate usually (mercury type), but
you need a good black body source for the IR cal session.
| |
| The Great Attractor 2007-05-08, 8:25 pm |
| On Tue, 08 May 2007 11:38:24 -0400, Chuck <no.spam@no.spam.at.all> wrote:
>John Larkin wrote:
>
>Don't forget that with your IR gun, the
>emissivity of the source is important in
>calibration.
Very good call, Chuck.
> I suspect water and ice are
>not friendly calibration sources.
Spot on <sic>!
> Maybe
>a black anodized heat sink that has been
>heated to some calibrated temperature
>would be a good source.
Not if the surface that got anodized was "shiny", as it were. A good
black body source is aluminum (thick) as it conducts heat fairly evenly,
but the ideal surface is a very matte finish, or even concentric rings
cut into the face and then painted or anodized after a grit blast
session.
Shiny is bad, which is why water is bad, despite it also being a very
good, even conductor of heat. The shiny surface reflects the IR back
into the medium, hence reduced emissivity.
> Does your gun
>have an emissivity adjustment?
You can find a fairly decent emissivity chart here, as well as a very
good primer on the subject:
http://www.mikroninfrared.com/App_N...iples_of_IR.pdf
| |
| The Great Attractor 2007-05-08, 8:25 pm |
| On Tue, 08 May 2007 08:44:00 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>On Tue, 08 May 2007 15:35:34 GMT, szekeres@pitt.edu (GregS) wrote:
>
>
>If you IR measure shiny copper or brass, what you're measuring is your
>own reflection.
Not really. It depends on the focal length of the instrument. Shiny
surfaces do reflect a lot of their IR emissions back down into the medium
however.
A mirror finish of nearly anything yields results based on reflections,
yet is still very dependent on the optical system utilized by the
instrument.
>
>I dab things with black whiteboard marker to improve the emissivity.
Not very much though... if at all. Surface quality is the most
determinant factor, not "color".
A sprinkling of copier toner would work better, but be much "messier".
Is that a "messier function"? :-]
>Apparently Scotch Magic tape has high emissivity, too.
Yes, but the underlying heat has to push through the tape medium, and
there are losses.
Any matte finish brings one closer to ideal. Flat black paint (very
thin coat) is best.
Take a look here for some really good facts:
http://www.mikroninfrared.com/App_N...iples_of_IR.pdf
| |
| The Great Attractor 2007-05-08, 8:25 pm |
| On Tue, 8 May 2007 09:10:23 -0700, "RST Engineering \(jw\)"
<jim@rstengineering.com> wrote:
>Ice mixed with distilled (or for your purposes, tap will be fine) water and
>allowed to rest for a few minutes will give you 32°F within millidegrees.
>Be sure to stir it every half minute or so to get the thermoclines well
>distributed.
For the thermocouple, sure. Add some salt even. Not good for the IR
tho.
>
>Boiling water at sea level will give you 212°F fairly accurately, less 1°F
>(for your stated accuracy) for every thousand feet of altitude you are above
>sea level up to a few thousand feet.
Boiling water is nebulous as one has to decide what "boiling" is, and a
hearty boil can well be far above the boiling start point was/is.
>
>Jim
>
Top posting is utterly retarded, boy.
You're a TOFU retard.
| |
| The Great Attractor 2007-05-08, 8:25 pm |
| On 8 May 2007 09:16:18 -0700, John O'Flaherty <quiasmox@yahoo.com> wrote:
>On May 8, 8:56 am, DaveC <m...@privacy.net> wrote:
>
>Not sure what you mean by "cheap", but you can get a YSI thermilinear
>network, which consists of a composite of three thermistors and some
>precision resistors for about $27. The one that goes from 0-100C
>claims +/- 0.15C accuracy (+/- 0.27F).
>That might be expensive for one calibration, but you might use it in
>the future.
>Then, you could get a black anodized heat sink with one side smooth,
>and drill little holes in the side, close to the flat surface, and
>insert the YSI thermistor and your thermocouple, maybe with some heat
>sink glop. Then point the IR detector at it. Let it go through some
>temperature changes slow enough that the whole thing has time to
>equlibrate, and collect some calibration data for both devices.
Pointing at the finned side would yield better emissivity than the
"smooth" side would.
Anodized, extruded Al usually has a fairly shiny surface quality.
The ideal black body source is a MATTE finish, so grit blasted Al with
some matte black paint (very thin coat) would be best/better.
Yields about a .97 Emissivity. The anodized Al (regardless of color)
yields about ten full points lower, if not worse.
Surface quality is a VERY important factor here.
Have a look here for a bit more info. Even though you seem very
knowledgeable about it, this should help.
The ideal source, of course, is a cavity.
http://www.mikroninfrared.com/App_N...iples_of_IR.pdf
| |
| The Great Attractor 2007-05-08, 8:25 pm |
| On Tue, 08 May 2007 17:15:53 GMT, DaveC <me@privacy.net> wrote:
>
>Re. the ice "calibration": as someone pointed out, ice & h2o isn't very
>IR-emissive, it it? Would it help to mix in a little black ink? (Lots lying
>around a print shop...)
Color isn't the issue. The surface of water is VERY reflective, so any
IR the medium generates get reflect BACK into the medium. This is why
water has such a poor emissivity.
A matte finish Aluminum block/box filled with a known temp water
(circulating) would likely be only a couple tenths of a degree off the
water temp, and would allow the IR gun to be calibrated very well.
| |
| The Great Attractor 2007-05-08, 8:25 pm |
| On Tue, 08 May 2007 18:05:49 GMT, Rich Grise <rich@example.net> wrote:
>I once used cigarette ashes and spit on a piece of aluminum. :-)
Miles off the mark, as usual.
| |
|
|
| The Great Attractor 2007-05-08, 8:25 pm |
| On Tue, 08 May 2007 12:20:02 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>The emissivity of the ice cube seems close to 1.0.
You're nuts.
| |
| The Great Attractor 2007-05-08, 8:25 pm |
| On Tue, 8 May 2007 12:45:00 -0700, "RST Engineering \(jw\)"
<jim@rstengineering.com> wrote:
>Talk about measuring with a micrometer, marking with chalk, and cutting with
>an axe!!!
>
>The fellow is looking for a couple of °F accuracy.
>
>Jim
And you are STILL a top posting Usenet RETARD!
Do you not notice the conventions used by others or are you always
deliberately fucking obtuse, boy?
| |
| The Great Attractor 2007-05-08, 8:25 pm |
| On Tue, 08 May 2007 15:00:14 -0500, Spehro Pefhany
<speffSNIP@interlogDOTyou.knowwhat> wrote:
>Yes, but I don't know how you're going to get a matt finish on the
>water. More importantly perhaps, the ink might alter the boiling
>point.
The term is matte.
Water is a bad idea for the IR, and the color doesn't matter.
The term for today is:
SURFACE QUALITY
http://www.mikroninfrared.com/App_N...iples_of_IR.pdf
| |
| Rich Grise 2007-05-08, 8:25 pm |
| On Tue, 08 May 2007 18:32:13 +0000, DaveC wrote:
>
> So where's the "standard" in this experiment?
Borrow somebody's calibrated DVM that has a temp. probe. :-)
Cheers!
Rich
| |
|
| On Tue, 08 May 2007 17:31:59 -0700, The Great Attractor
<SuperM@ssiveBlackHoleAtTheCenterOfTheMilkyWayGalaxy.org> wrote:
>On Tue, 8 May 2007 09:10:23 -0700, "RST Engineering \(jw\)"
><jim@rstengineering.com> wrote:
>
>
> For the thermocouple, sure. Add some salt even. Not good for the IR
>tho.
>
> Boiling water is nebulous as one has to decide what "boiling" is, and a
>hearty boil can well be far above the boiling start point was/is.
>
>
> Top posting is utterly retarded, boy.
>
>
> You're a TOFU retard.
You're a retarded dickheck who know nothing about which you speak.
--
Usenet lits score:
GIT-R-DONE!
#20 Usenet XXXXXXX
#6 Lits Slut
#11 Most posting trolls/hunters/flonkers 2007
| |
|
| On Tue, 08 May 2007 17:44:25 -0700, The Great Attractor
<SuperM@ssiveBlackHoleAtTheCenterOfTheMilkyWayGalaxy.org> wrote:
How's the tracking coming along retard?
>On Tue, 8 May 2007 12:45:00 -0700, "RST Engineering \(jw\)"
><jim@rstengineering.com> wrote:
>
>
>
> And you are STILL a top posting Usenet RETARD!
>
> Do you not notice the conventions used by others or are you always
>deliberately fucking obtuse, boy?
--
Usenet lits score:
GIT-R-DONE!
#20 Usenet XXXXXXX
#6 Lits Slut
#11 Most posting trolls/hunters/flonkers 2007
| |
| The Great Attractor 2007-05-08, 8:25 pm |
| On Tue, 08 May 2007 14:16:38 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>
>My FLIR rep confirms: water is 0.98.
>
Hard to believe, but it is.
Still, not a good source to cal IR with.
Skin is about 0.96, but skin temp is always several degrees lower than
internal body temp.
A GOOD, NIST traceable black body source is only about 0.98
1.0 is not achievable.
| |
| The Great Attractor 2007-05-08, 8:25 pm |
| On Tue, 08 May 2007 14:41:47 -0700, Tim Wescott <tim@seemywebsite.com>
wrote:
>
>There are only a few companies that actually manufacture imagers (FLIR
>Sweden is one). So many companies that "make" IR imagers are just
>plopping an OEM module made by someone else into their case.
>
K. Irani invented the "resistor bolometer" back in 1960.
http://www.mikroninfrared.com/
They have imagers, but likely get their sensors from an OEM house, as
does FLIR most likely. Chip fabs ain't cheap endeavors.
The best thing about a good IR device maker is the electronics behind
the instrument.
FLIR buys their calibration sources from these guys.
These guys are the top dogs in non-contact temperature measurement.
We made some that are still in use at the shuttle launch pads that have
the longest IR focal length made for a calibrated instrument.
The observation shacks are 1000' from the pad, and the instruments
observe a ten foot spot, and detect a 200° C change within a one foot
spot in that circle (1° FOV). The area observed is known as "the
protected area". It is near the blast chutes on the pad.
When IR imagery was in its infancy, their device was $90,000, and was 4
frames per second, and we had early 386s back then, and there was not
even a way to get the images off onto VHS. At least it was 16 colors.:-]
We also had one that looked through a microscope.
Now, they are likely 16 bit color, and the image data can be manipulated
post capture. These guys are pretty good.
I used to build a 2.5 foot by 4 inch, gold mirrored, rifle stock and
scoped analog unit that power companies used to point at insulators and
transformers to get status without having to climb poles or towers.
Now, they just point an imager at them. And a fairly cheap one at
that.
The world has come a long way since '87.
Here's a good primer:
http://www.mikroninfrared.com/App_N...iples_of_IR.pdf
| |
| The Great Attractor 2007-05-08, 8:25 pm |
| On Wed, 09 May 2007 00:47:19 GMT, Rich Grise <rich@example.net> wrote:
>On Tue, 08 May 2007 18:32:13 +0000, DaveC wrote:
>
>
>Borrow somebody's calibrated DVM that has a temp. probe. :-)
>
The probe also has to be calibrated. Ideally, NIST traceable with a
correction chart provided.
| |
| MooseFET 2007-05-08, 9:25 pm |
| On May 8, 12:20 pm, John Larkin
<jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
> On Tue, 08 May 2007 17:15:53 GMT, DaveC <m...@privacy.net> wrote:
>
>
>
>
> If you use a stainless thermos or Starbucks coffee mug thing, and fill
> it with stirred crushed ice and water, and fire an ir sensor down into
> that, it should be pretty good.
>
> I've got an ice cube on a paper plate on my desk, just starting to
> melt. Our FLIR thermal imager shows it at about +0.5C, and a cheap
> Extech IR thermometer claims -2C.
>
> The emissivity of the ice cube seems close to 1.0. As I image it and
> wave my hand around nearby, there's no hint of thermal reflections or
> temperature change, so it's almost totally black in the thermal IR.
>
> Oh my red plastic Presidential Water Cup is on my desk, too, with
> about an inch of water in the bottom. It reads 6.8C with a
> thermocouple, 7.0 on the FLIR, and 4C on the Extech. Again, no hint of
> reflections. So water also looks black at thermal wavelengths.
>
> John
I couldn't find the paper I wass looking for but I did find this:
http://www.google.com/url?sa=t&ct=r..._S6njvIsn2ojJag
I assume that the thermometer works around 5000nM. This would give a
good slope with ordinary temperatures.
| |
| John Larkin 2007-05-09, 3:25 am |
| On Tue, 08 May 2007 17:29:04 -0700, The Great Attractor
<SuperM@ssiveBlackHoleAtTheCenterOfTheMilkyWayGalaxy.org> wrote:
>On Tue, 08 May 2007 08:44:00 -0700, John Larkin
><jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>
>
> Not really. It depends on the focal length of the instrument. Shiny
>surfaces do reflect a lot of their IR emissions back down into the medium
>however.
How can the focal length change the emmisivity or the effective
temperature? If the surface is a mirror in the thermal IR, all you
ever image is a reflection of *something*, but you don't measure the
temperature of the mirror itself. Shiny copper has an emissivity of
about 0.05, so 95% of whatever the IR meter is seeing is the
reflection of something else.
> A mirror finish of nearly anything yields results based on reflections,
>yet is still very dependent on the optical system utilized by the
>instrument.
>
>
> Not very much though... if at all. Surface quality is the most
>determinant factor, not "color".
Having tested a number of ways to increase the emissivity of shiny
metallic surfaces, I know that black whiteboard marker brings the
emissivity almost all the way up to 1.0. And it's easy to wipe off
after you're done. Is 1.0 within your definition of "if at all"?
>
> A sprinkling of copier toner would work better, but be much "messier".
>
> Is that a "messier function"? :-]
>
>
> Yes, but the underlying heat has to push through the tape medium, and
>there are losses.
Do the math. Delta-t across scotch tape, working against air, is
usually tiny.
>
> Any matte finish brings one closer to ideal. Flat black paint (very
>thin coat) is best.
Gosh, didn't somebody recently say that
'Surface quality is the most determinant factor, not "color"'?
>
> Take a look here for some really good facts:
>
>http://www.mikroninfrared.com/App_N...iples_of_IR.pdf
Funny, they keep mentioning "black" too.
John
| |
| John Larkin 2007-05-09, 3:25 am |
| On Tue, 08 May 2007 17:42:08 -0700, The Great Attractor
<SuperM@ssiveBlackHoleAtTheCenterOfTheMilkyWayGalaxy.org> wrote:
>On Tue, 08 May 2007 12:20:02 -0700, John Larkin
><jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>
>
>
> You're nuts.
What do you think the emissivity of an ice cube is?
John
| |
| John Larkin 2007-05-09, 3:25 am |
| On Tue, 08 May 2007 17:16:56 -0700, The Great Attractor
<SuperM@ssiveBlackHoleAtTheCenterOfTheMilkyWayGalaxy.org> wrote:
>On 8 May 2007 08:14:10 -0700, MooseFET <kensmith@rahul.net> wrote:
>
>Freezing point and melting point are also pressure related, and so they
>too vary.
>
> Also, water has a very low emissivity, and would be a very poor choice
>for a reading on the IR instrument.
0.98, about as high as anything else on the planet.
John
| |
| John Larkin 2007-05-09, 3:25 am |
| On Tue, 08 May 2007 17:39:39 -0700, The Great Attractor
<SuperM@ssiveBlackHoleAtTheCenterOfTheMilkyWayGalaxy.org> wrote:
>On Tue, 08 May 2007 17:15:53 GMT, DaveC <me@privacy.net> wrote:
>
>
>
> Color isn't the issue. The surface of water is VERY reflective, so any
>IR the medium generates get reflect BACK into the medium. This is why
>water has such a poor emissivity.
>
> A matte finish Aluminum block/box filled with a known temp water
>(circulating) would likely be only a couple tenths of a degree off the
>water temp, and would allow the IR gun to be calibrated very well.
Take a look here for some really good facts:
http://www.mikroninfrared.com/App_N...iples_of_IR.pdf
Water = 0.98
Aluminum varies from 0.04 to 0.3 depending on finish, absolutely
useless for IR temperature measurement.
AlwaysWrong.
John
| |
| John Larkin 2007-05-09, 3:25 am |
| On Tue, 08 May 2007 17:46:11 -0700, The Great Attractor
<SuperM@ssiveBlackHoleAtTheCenterOfTheMilkyWayGalaxy.org> wrote:
>On Tue, 08 May 2007 15:00:14 -0500, Spehro Pefhany
><speffSNIP@interlogDOTyou.knowwhat> wrote:
>
>
>
> The term is matte.
>
> Water is a bad idea for the IR, and the color doesn't matter.
>
> The term for today is:
>
> SURFACE QUALITY
>
>http://www.mikroninfrared.com/App_N...iples_of_IR.pdf
You keep posting this link, so why don;t you *read* it?
Water has a thermal IR emissivity of 0.98, about as black as anything
gets.
John
| |
|
| > If you use a stainless thermos or Starbucks coffee mug thing, and fill
> it with stirred crushed ice and water, and fire an ir sensor down into
> that, it should be pretty good.
>
> I've got an ice cube on a paper plate on my desk, just starting to
> melt. Our FLIR thermal imager shows it at about +0.5C, and a cheap
> Extech IR thermometer claims -2C.
>
> The emissivity of the ice cube seems close to 1.0. As I image it and
> wave my hand around nearby, there's no hint of thermal reflections or
> temperature change, so it's almost totally black in the thermal IR.
>
> Oh my red plastic Presidential Water Cup is on my desk, too, with
> about an inch of water in the bottom. It reads 6.8C with a
> thermocouple, 7.0 on the FLIR, and 4C on the Extech. Again, no hint of
> reflections. So water also looks black at thermal wavelengths.
>
> John
Nothing like a little actual data to cut through the fog...
> My FLIR rep confirms: water is 0.98.
>
> John
or a little confirmation from them that depends on this stuff for their
income...
[...][color=darkred]
> Water has a thermal IR emissivity of 0.98, about as black as anything
> gets.
>
> John
Or an oft-referenced expert source.
Thanks again, John.
Dave (OP)
--
DaveC
me@bogusdomain.net
This is an invalid return address
Please reply in the news group
| |
| The Great Attractor 2007-05-09, 3:25 am |
| On Tue, 08 May 2007 19:36:52 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>How can the focal length change the emmisivity or the effective
>temperature?
Can you really be that dumb?
If the instrument has a one inch focus, your reflection is hardly going
to affect what it reads from the face of a "shiny piece of copper". It
will read the copper, and be off be the emissivity factor.
Focus is extremely important in the energy gathered by an IR
instrument. EXTREMELY. Do you think the 1000' focus device looking at
the space shuttle launch pad would get enough energy to give a calibrated
reading if it were focused for 20 feet, despite being 1000' away from the
target being measured?
Use some common sense, man.
| |
| The Great Attractor 2007-05-09, 3:25 am |
| On Tue, 08 May 2007 19:36:52 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>
>Having tested a number of ways to increase the emissivity of shiny
>metallic surfaces, I know that black whiteboard marker brings the
>emissivity almost all the way up to 1.0.
You're an idiot, and there are NO 1.0 emissivity sources.
> And it's easy to wipe off
>after you're done. Is 1.0 within your definition of "if at all"?
I think you need to re-learn what is in the realm of possibility. Try
the PDF I posted a link to for starters.
| |
| The Great Attractor 2007-05-09, 3:25 am |
| On Tue, 08 May 2007 19:36:52 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>Do the math. Delta-t across scotch tape, working against air, is
>usually tiny.
It isn't the gradient across it, it is what it inhibits THROUGH it. It
does have good surface quality for high emissivity, however.I merely
stated that there would be losses.
| |
| The Great Attractor 2007-05-09, 3:25 am |
| On Tue, 08 May 2007 19:36:52 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>Gosh, didn't somebody recently say that
>
>'Surface quality is the most determinant factor, not "color"'?
Yes.It was me, and a MATTE finish (flat black paint) WILL yield a BETTER
surface quality with reference to IR readings than a shiny surface will.
| |
| The Great Attractor 2007-05-09, 3:25 am |
| On Tue, 08 May 2007 19:42:04 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>On Tue, 08 May 2007 17:42:08 -0700, The Great Attractor
><SuperM@ssiveBlackHoleAtTheCenterOfTheMilkyWayGalaxy.org> wrote:
>
>
>What do you think the emissivity of an ice cube is?
>
>John
>
List all the 1.0 emissivity sources you know of.
| |
| The Great Attractor 2007-05-09, 3:25 am |
| On Tue, 08 May 2007 19:50:48 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>Water = 0.98
>
>Aluminum varies from 0.04 to 0.3 depending on finish, absolutely
>useless for IR temperature measurement.
>
>AlwaysWrong.
>
Unfinished Al, you retarded fuck.
Aluminum is, in fact, what they and nearly ALL makers of low and medium
temp black body calibration sources use for their black body faces.
Mikron does, NIST certifies.
What was that, jackass? The REAL world can't hear you!
They use a big 5 pound ingot of AL with a single rod heater shoved into
the back of it. The face gets concentric rings that look like someone
threaded the face of it, and then THAT gets painted with the black body
paint mentioned in the same PDF YOU quoted from, dipshit.
The gradient across the face is less than 0.1° C from center to about
1/4" from the edge of a 5.5" cylindrical ingot about 3.5" inches thick.
NIST buys them. NIST certifies them for their customers... where does
that leave your retarded XXX.
Oh yeah... FUCKING WRONG... again.
The high temp sources are refractory media cavities where the
instrument look into the cavity through a ceramic tube.
You are lost, fucker.
| |
| The Great Attractor 2007-05-09, 3:25 am |
| On Tue, 08 May 2007 20:50:17 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>On Tue, 08 May 2007 17:46:11 -0700, The Great Attractor
><SuperM@ssiveBlackHoleAtTheCenterOfTheMilkyWayGalaxy.org> wrote:
>
>
>
>You keep posting this link, so why don;t you *read* it?
>
>Water has a thermal IR emissivity of 0.98, about as black as anything
>gets.
>
>John
>
But it has a very high surface reflection issue, and it gives off a
vapor above room temp. Badly as temp increases. IR instruments need
precise focal distances to get calibrated correctly.
Nice try, FUCKING WRONG... again.
Get a clue, boy.
| |
| The Great Attractor 2007-05-09, 3:25 am |
| On Wed, 09 May 2007 04:10:30 GMT, DaveC <me@privacy.net> wrote:
>Or an oft-referenced expert source.
>
>Thanks again, John.
>Dave (OP)
The expert source would certainly NOT be john, and the link was from
ME, XXXXXXX.
| |
| John Larkin 2007-05-09, 3:25 am |
| On Tue, 08 May 2007 21:51:53 -0700, The Great Attractor
<SuperM@ssiveBlackHoleAtTheCenterOfTheMilkyWayGalaxy.org> wrote:
>On Wed, 09 May 2007 04:10:30 GMT, DaveC <me@privacy.net> wrote:
>
>
> The expert source would certainly NOT be john, and the link was from
>ME, XXXXXXX.
Well read it then. Water is 0.98.
John
| |
| John Larkin 2007-05-09, 3:25 am |
| On Tue, 08 May 2007 21:48:37 -0700, The Great Attractor
<SuperM@ssiveBlackHoleAtTheCenterOfTheMilkyWayGalaxy.org> wrote:
>On Tue, 08 May 2007 19:50:48 -0700, John Larkin
><jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>
>
> Unfinished Al, you retarded fuck.
>
> Aluminum is, in fact, what they and nearly ALL makers of low and medium
>temp black body calibration sources use for their black body faces.
>
> Mikron does, NIST certifies.
>
> What was that, jackass? The REAL world can't hear you!
>
> They use a big 5 pound ingot of AL with a single rod heater shoved into
>the back of it. The face gets concentric rings that look like someone
>threaded the face of it, and then THAT gets painted with the black body
>paint mentioned in the same PDF YOU quoted from, dipshit.
Then it's the paint that has high emissivity, not the aluminum. The
aluminum is just a heat spreader. Copper would be twice as good.
And water is still 0.98, about as black as anything gets. My tests
this afternoon showed neither water nor ice is the slightest "shiny"
at thermal wavelengths. If it were, its e value would be much less,
and my melting ice cube wouldn't have read 0.5C on the FLIR.
John
| |
| Robert Baer 2007-05-09, 3:25 am |
| DaveC wrote:
> I know this subject of "cheap" and "calibrate" used in the same sentence may
> well be anathema to some of you but I need to verify that either my IR temp
> gun is accurate or my DMM/thermocouple is, or neither. Accuracy to 2 or 3
> degrees F is fine.
>
> I'm looking for suggestions for a simple way to provide some kind of common
> temperature "standard" (I use the term loosely, here) I can compare these
> against.
>
> Thanks,
Use a melting ice cube for zero C, and boiling distilled water (in a
clean container) for 100 C.
| |
| Robert Latest 2007-05-09, 3:25 am |
| ["Followup-To:" header set to sci.electronics.design.]
The Great Attractor wrote:
> On Tue, 08 May 2007 19:42:04 -0700, John Larkin
><jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>
> List all the 1.0 emissivity sources you know of.
What part of "close to" do you not understand?
robert
| |
| Robert Latest 2007-05-09, 3:25 am |
| ["Followup-To:" header set to sci.electronics.design.]
The Great Attractor wrote:
> Shiny is bad, which is why water is bad,
[...]
> http://www.mikroninfrared.com/App_N...iples_of_IR.pdf
Are you illiterate? Why don't you look up water in the data YOU provide and
see for yourself how shiny it is? Hint 0.98 isn't shiny. 0.98 is about as
black as it gets.
robert
| |
| Robert Latest 2007-05-09, 3:25 am |
| ["Followup-To:" header set to sci.electronics.design.]
The Great Attractor wrote:
> On Tue, 08 May 2007 19:36:52 -0700, John Larkin
><jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>
>
> You're an idiot, and there are NO 1.0 emissivity sources.
I agree that illiteracy combined with extreme stupidity is a tough burden to
carry.
robert
| |
| Tony Williams 2007-05-09, 3:25 am |
| In article <odn243hqq30jfv1e5hfmbbqjqdm3prkik3@4ax.com>,
John Larkin <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
> And water is still 0.98, about as black as anything gets. My
> tests this afternoon showed neither water nor ice is the
> slightest "shiny" at thermal wavelengths. If it were, its e value
> would be much less, and my melting ice cube wouldn't have read
> 0.5C on the FLIR.
www.icess.ucsb.edu/modis/EMIS/html/em.html
It shows ice/water having a very high emissivity.
--
Tony XXXXXXXX.
| |
| The Great Attractor 2007-05-09, 9:25 am |
| On Tue, 08 May 2007 22:34:34 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>On Tue, 08 May 2007 21:51:53 -0700, The Great Attractor
><SuperM@ssiveBlackHoleAtTheCenterOfTheMilkyWayGalaxy.org> wrote:
>
>
>
>Well read it then. Water is 0.98.
>
Read my previous posts. I Know what it is.
Nice job of being immature again, FUCKING WRONG.
| |
| The Great Attractor 2007-05-09, 9:25 am |
| On Tue, 08 May 2007 22:42:31 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>Then it's the paint that has high emissivity, not the aluminum. The
>aluminum is just a heat spreader. Copper would be twice as good.
No, it wouldn't because it is four times more expensive, and it's
electrical conductivity and its thermal conductivity are not the same,
asswipe.
Alumininum is he right medium conduction wise, AND it is the right
medium cost wise. The coating on eother would yield the same result so
any point you thought you were making is moot.
You need to get off you "fuck with dark matter" high horse, and get
back to reality, boy.
The KeithTard, and the Grisetard can't fuck with me, so what makes you
think you can, dipshit?
| |
| The Great Attractor 2007-05-09, 9:25 am |
| On Tue, 08 May 2007 22:42:31 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>And water is still 0.98, about as black as anything gets.
absolutely the wrong choice though. It is unstable, and gives off
vapors, throwing off surface conditions, which is what an imager MUST
focus on to get reliable calibration data.
| |
|
| On Wed, 09 May 2007 02:23:33 -0700, The Great Attractor
<SuperM@ssiveBlackHoleAtTheCenterOfTheMilkyWayGalaxy.org> wrote:
>On Tue, 08 May 2007 22:42:31 -0700, John Larkin
><jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>
>
>
> No, it wouldn't because it is four times more expensive, and it's
>electrical conductivity and its thermal conductivity are not the same,
>asswipe.
>
> Alumininum is he right medium conduction wise, AND it is the right
>medium cost wise. The coating on eother would yield the same result so
>any point you thought you were making is moot.
>
> You need to get off you "fuck with dark matter" high horse, and get
>back to reality, boy.
>
> The KeithTard, and the Grisetard can't fuck with me, so what makes you
>think you can, dipshit?
I have been for weeks, it's easy.
--
Usenet lits score:
GIT-R-DONE!
#20 Usenet XXXXXXX
#6 Lits Slut
#11 Most posting trolls/hunters/flonkers 2007
| |
| MooseFET 2007-05-09, 9:25 am |
| On May 8, 10:34 pm, John Larkin
<jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
> On Tue, 08 May 2007 21:51:53 -0700, The Great Attractor
>
> <Sup...@ssiveBlackHoleAtTheCenterOfTheMilkyWayGalaxy.org> wrote:
>
>
>
>
> Well read it then. Water is 0.98.
Why do you even bother reading his posts? He is wrong far more often
than right and never admits an error.
| |
| MooseFET 2007-05-09, 9:25 am |
| On May 8, 11:26 pm, Robert Baer <robertb...@earthlink.net> wrote:
> DaveC wrote:
>
>
>
> Use a melting ice cube for zero C, and boiling distilled water (in a
> clean container) for 100 C.
Actually, the international standard is a bunch ice covered in water a
stirred well. The standard clearly says that this must be done in
your own coffee cup and the stirring must be done with a plastic
coffee stirrer. You have to stir it up while standing in the company
kitchen and then measure as soon as you are done stirring. You can't
stop to answer the "What the heck are you doing?" question from the
cute accountant.
| |
| John Larkin 2007-05-09, 1:25 pm |
| On Tue, 08 May 2007 21:38:24 -0700, The Great Attractor
<SuperM@ssiveBlackHoleAtTheCenterOfTheMilkyWayGalaxy.org> wrote:
>On Tue, 08 May 2007 19:36:52 -0700, John Larkin
><jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>
>
> You're an idiot, and there are NO 1.0 emissivity sources.
Did you miss the word "almost"? 3rd line, 2nd word in my paragraph
above.
With an imager, it takes a few seconds to test a surface to get a
pretty good idea of its emissivity. The whiteboard marker, and the
water, and the ice cube, all passed my tests for "so black that it
doesn't matter", or, equivalently, "almost 1.0"
> I think you need to re-learn what is in the realm of possibility. Try
>the PDF I posted a link to for starters.
I read it; you didn't.
John
| |
| John Larkin 2007-05-09, 1:25 pm |
| On 9 May 2007 06:33:01 -0700, MooseFET <kensmith@rahul.net> wrote:
>On May 8, 10:34 pm, John Larkin
><jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
>
>Why do you even bother reading his posts? He is wrong far more often
>than right and never admits an error.
Ok, he is AlwaysWrong. But when a sensible person asks a sensible
question, and the GreatBlunderer gives him advice that is flat
preposterous, he ought to be corrected.
John
| |
| John Larkin 2007-05-09, 1:25 pm |
| On Wed, 09 May 2007 02:23:33 -0700, The Great Attractor
<SuperM@ssiveBlackHoleAtTheCenterOfTheMilkyWayGalaxy.org> wrote:
>On Tue, 08 May 2007 22:42:31 -0700, John Larkin
><jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>
>
>
> No, it wouldn't because it is four times more expensive, and it's
>electrical conductivity and its thermal conductivity are not the same,
Both are about 2:1 better than aluminum. The factor is even higher
compared to common aluminum alloys; hardly anybody wants to machine
pure aluminum, and the alloying wrecks both the electrical and thermal
conductivity.
>
> The KeithTard, and the Grisetard can't fuck with me, so what makes you
>think you can, dipshit?
You fuck with yourself. Or job is to laugh.
John
| |
| MooseFET 2007-05-09, 1:25 pm |
| On May 9, 7:53 am, John Larkin
<jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
> On 9 May 2007 06:33:01 -0700, MooseFET <kensm...@rahul.net> wrote:
>
>
>
>
>
>
>
>
>
>
> Ok, he is AlwaysWrong. But when a sensible person asks a sensible
> question, and the GreatBlunderer gives him advice that is flat
> preposterous, he ought to be corrected.
Yes, I can see your point.
Perhaps someone as a service to the public could write a little bot
that puts a follow up on his posts pointing his out.
| |
| MooseFET 2007-05-09, 1:25 pm |
| On May 9, 7:56 am, John Larkin
[......]
> Both are about 2:1 better than aluminum. The factor is even higher
> compared to common aluminum alloys; hardly anybody wants to machine
> pure aluminum, and the alloying wrecks both the electrical and thermal
> conductivity.
In all metals, the thermal and electrical conductivity track each
other quite nicely. Copper alloys such as brass are way less
conductive. The atomic clock folks use a copper alloy that is very
resistive to make heaters.
>
>
>
>
> You fuck with yourself. Or job is to laugh.
>
> John
| |
|
| >>> Or an oft-referenced expert source.
[color=darkred]
The "expert source" I'm referring to is the document you pointed to several
times.
--
DaveC
me@bogusdomain.net
This is an invalid return address
Please reply in the news group
| |
| John O'Flaherty 2007-05-09, 1:25 pm |
| On May 8, 1:45 pm, "RST Engineering \(jw\)" <j...@rstengineering.com>
wrote:
> Talk about measuring with a micrometer, marking with chalk, and cutting w=
ith
> an axe!!!
>
> The fellow is looking for a couple of =B0F accuracy.
True. But this may not be the last temperature measurement he'll ever
make.
--
John
| |
| Michael A. Terrell 2007-05-09, 5:25 pm |
| MooseFET wrote:
>
> Yes, I can see your point.
>
> Perhaps someone as a service to the public could write a little bot
> that puts a follow up on his posts pointing his out.
So, you need a "Garbage bot"? ;-)
--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.
Michael A. Terrell
Central Florida
| |
| John Larkin 2007-05-09, 5:25 pm |
| On Tue, 08 May 2007 21:36:47 -0700, The Great Attractor
<SuperM@ssiveBlackHoleAtTheCenterOfTheMilkyWayGalaxy.org> wrote:
>On Tue, 08 May 2007 19:36:52 -0700, John Larkin
><jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>
>
>
> Can you really be that dumb?
>
> If the instrument has a one inch focus, your reflection is hardly going
>to affect what it reads from the face of a "shiny piece of copper". It
>will read the copper, and be off be the emissivity factor.
Hhat can I say but WrongAgain?
Look into a mirror that's reflecting the sky into your eyes. You see
the color of the sky. Now take off your glasses or equivalent to
defocus the scene. You still see the color of the sky.
>
> Focus is extremely important in the energy gathered by an IR
>instrument. EXTREMELY. Do you think the 1000' focus device looking at
>the space shuttle launch pad would get enough energy to give a calibrated
>reading if it were focused for 20 feet, despite being 1000' away from the
>target being measured?
If defocussing means you are averaging unwanted objects into the image
with the desired target, sure you need to focus. But no amount of
focussing, from any distance, will make the emissivity of shiny copper
any better, or improve the temperature measuring accurscy.
If you poke the germanium lens one inch away from the copper, and
focus perfectly, you'll be measuring mostly the reflection, namely the
temperature of the lens itself, not the temp of the copper. Try it.
>
> Use some common sense, man.
OK, common sense: look in a mirror. You see your face, not the mirror.
Get closer; you still see your face, not the mirror.
Try it.
John
| |
| John Larkin 2007-05-09, 5:25 pm |
| On Tue, 08 May 2007 21:50:48 -0700, The Great Attractor
<SuperM@ssiveBlackHoleAtTheCenterOfTheMilkyWayGalaxy.org> wrote:
>On Tue, 08 May 2007 20:50:17 -0700, John Larkin
><jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>
> But it has a very high surface reflection issue,
OK, positively the last time:
IF THE EMISSIVITY IS 0.98, IT CAN'T BE REFLECTIVE IN THE THERMAL IR.
And while you're at it, check your own link for the emissivity of
glass. And smooth ice.
John
| |
| John Larkin 2007-05-09, 5:25 pm |
| On 9 May 2007 08:25:39 -0700, MooseFET <kensmith@rahul.net> wrote:
>On May 9, 7:56 am, John Larkin
>[......]
>
>In all metals, the thermal and electrical conductivity track each
>other quite nicely. Copper alloys such as brass are way less
>conductive. The atomic clock folks use a copper alloy that is very
>resistive to make heaters.
>
>
Most pure metals run right around 150,000 k/w per ohm. Brass seems to
be higher, something like 250,000.
John
| |
| John O'Flaherty 2007-05-09, 5:25 pm |
| On May 8, 6:36 pm, The Great Attractor
<Sup...@ssiveBlackHoleAtTheCenterOfTheMilkyWayGalaxy.org> wrote:
> On 8 May 2007 09:16:18 -0700, John O'Flaherty <quias...@yahoo.com> wrote:
>
>
>
>
>
>
> Pointing at the finned side would yield better emissivity than the
> "smooth" side would.
I mentioned the flat side because I wanted the sensors to be close to,
and so at the same temperature, as the surface. The fins could easily
be at a different average temperature.
> Anodized, extruded Al usually has a fairly shiny surface quality.
>
> The ideal black body source is a MATTE finish, so grit blasted Al with
> some matte black paint (very thin coat) would be best/better.
>
> Yields about a .97 Emissivity. The anodized Al (regardless of color)
> yields about ten full points lower, if not worse.
>
> Surface quality is a VERY important factor here.
>
> Have a look here for a bit more info. Even though you seem very
> knowledgeable about it, this should help.
>
> The ideal source, of course, is a cavity.
>
> http://www.mikroninfrared.com/App_N...iples_of_IR.pdf
Thanks for the interesting link. I note that it shows a very common,
inexpensive material, black cloth, with an uncommonly high emissivity:
0.98. With this information, I'd change my suggestion to using a
flattish copper block (highest possible thermal conductivity) of a
size to take up the viewing area of the IR meter, holes and sensors as
before, and with a piece of black cloth glued to the surface. I think
the whole thing would be inexpensive and fairly accurate.
--
John
| |
| The Great Attractor 2007-05-09, 8:25 pm |
| On 9 May 2007 06:33:01 -0700, MooseFET <kensmith@rahul.net> wrote:
>On May 8, 10:34 pm, John Larkin
><jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
>
>Why do you even bother reading his posts? He is wrong far more often
>than right and never admits an error.
You just made one, fuckhead.
| |
| The Great Attractor 2007-05-09, 8:25 pm |
| On Wed, 09 May 2007 07:53:34 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>
>Ok, he is AlwaysWrong. But when a sensible person asks a sensible
>question, and the GreatBlunderer gives him advice that is flat
>preposterous, he ought to be corrected.
>
>John
What was "preposterous", you absolute fucking retard that can't even
operate a vapor phase degreaser properly?
| |
| The Great Attractor 2007-05-09, 8:25 pm |
| On Wed, 09 May 2007 07:56:39 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>
>Both are about 2:1 better than aluminum. The factor is even higher
>compared to common aluminum alloys; hardly anybody wants to machine
>pure aluminum, and the alloying wrecks both the electrical and thermal
>conductivity.
You don't get it. If the surface (read that word carefully, idiot) is
prepared correctly, a 0.98 emissivity is achieved, and AL makes an
EXCELLENT black body source, and it is used in the industry EVERY DAY.
So fuck off, you goddamned retard.
| |
| The Great Attractor 2007-05-09, 8:25 pm |
| On 9 May 2007 08:18:49 -0700, MooseFET <kensmith@rahul.net> wrote:
>Yes, I can see your point.
>
>Perhaps someone as a service to the public could write a little bot
>that puts a follow up on his posts pointing his out.
Point my *what* out? My massive prong?
Bwuahahahaha! You fucking retards are hilarious.
| |
| The Great Attractor 2007-05-09, 8:25 pm |
| On Wed, 09 May 2007 15:41:12 GMT, DaveC <me@privacy.net> wrote:
>
>
>The "expert source" I'm referring to is the document you pointed to several
>times.
Yet you complimented HIM for posting it.
Nice reply to me. I really enjoy helping someone out, and then seeing
them complimenting someone else for it. Thanks.
| |
| The Great Attractor 2007-05-09, 8:25 pm |
| On 9 May 2007 09:36:32 -0700, John O'Flaherty <quiasmox@yahoo.com> wrote:
>On May 8, 1:45 pm, "RST Engineering \(jw\)" <j...@rstengineering.com>
>wrote:
>
>True. But this may not be the last temperature measurement he'll ever
>make.
Similar to imagery. One should always take the highest resolution shot
possible, so that it can be used in any circumstance form a low res paste
to a hi res utilization.
Calibrating an instrument should always involve a known source that is
of a HIGHER resolution that the instrument itself is.
If a source that equals the instrument's accuracy is used the error
level in the two can chain together. In fact, it is termed as "chaining
error".
| |
|
| On Wed, 09 May 2007 17:52:14 -0700, The Great Attractor
<SuperM@ssiveBlackHoleAtTheCenterOfTheMilkyWayGalaxy.org> wrote:
>On Wed, 09 May 2007 07:56:39 -0700, John Larkin
><jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>
>
>
> You don't get it. If the surface (read that word carefully, idiot) is
>prepared correctly, a 0.98 emissivity is achieved, and AL makes an
>EXCELLENT black body source, and it is used in the industry EVERY DAY.
>
> So fuck off, you goddamned retard.
PLONK
--
Usenet lits score:
GIT-R-DONE!
#20 Usenet XXXXXXX
#6 Lits Slut
#11 Most posting trolls/hunters/flonkers 2007
| |
| MooseFET 2007-05-09, 9:25 pm |
| On May 9, 12:37 pm, "Michael A. Terrell" <mike.terr...@earthlink.net>
wrote:
> MooseFET wrote:
>
>
>
> So, you need a "Garbage bot"? ;-)
It wasn't for me personally. I was concerned about anyone who may not
have seen his posts before. Since he seems to specialize in lame
insults and counterfactual statements, I don't read his posts much
anymore. When someone replies to him, I may read the reply. Someone
new to the group, however, may not know this about him.
| |
| Michael A. Terrell 2007-05-09, 9:25 pm |
| MooseFET wrote:
>
> On May 9, 12:37 pm, "Michael A. Terrell" <mike.terr...@earthlink.net>
> wrote:
>
> It wasn't for me personally. I was concerned about anyone who may not
> have seen his posts before. Since he seems to specialize in lame
> insults and counterfactual statements, I don't read his posts much
> anymore. When someone replies to him, I may read the reply. Someone
> new to the group, however, may not know this about him.
How about a simple warning post, once a week about the losers who
spread false and dangerous info?
--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.
Michael A. Terrell
Central Florida
| |
| MooseFET 2007-05-09, 9:25 pm |
| On May 9, 6:31 pm, "Michael A. Terrell" <mike.terr...@earthlink.net>
wrote:
> MooseFET wrote:
>
>
>
>
>
>
> How about a simple warning post, once a week about the losers who
> spread false and dangerous info?
One of the local news groups I used to frequent had a monthly FAQ
posting. There was an unoffical "keeper of the FAQ" who would edit it
from time to time and post it about once a month unless it was raining
or too sunny that week.
It worked moderately well. From time to time a newby would jump in
with a post before reading it and get gently roasted over the open
flames. When spam ads were posted we would have a little competition
to see who could write the best parody of it.
| |
| Jerry G. 2007-05-09, 9:25 pm |
| You really need a set of temperature standards. Temperature standard
equipment is expensive.
On a laser temperature reader, there is the EMS "emisivity) factor.
You must set the EMS of the reader to be proper for the type of object
you are measuring. If the EMS is not adjustable on your reader, then
the reference object must be of the correct colour and type of
material to be referenced.
If your reader is expensive to replace, I would suggest you send it to
a calibration lab that can check these types of units.
A crude way of checking the temperature accuracy is to use ice water
with crushed ice, and measure the water. This should read within about
0.5 C under ideal conditions. You can boil some water, but the
borametric pressure facture must be considered. This should be able to
reference to within about 0.5 C. The water must be purified water.
Tap water will have minerals in it, and its boiling point will be
effected.
Jerry G
=====
On May 8, 10:56 am, DaveC <m...@privacy.net> wrote:
> I know this subject of "cheap" and "calibrate" used in the same sentence may
> well be anathema to some of you but I need to verify that either my IR temp
> gun is accurate or my DMM/thermocouple is, or neither. Accuracy to 2 or 3
> degrees F is fine.
>
> I'm looking for suggestions for a simple way to provide some kind of common
> temperature "standard" (I use the term loosely, here) I can compare these
> against.
>
> Thanks,
> --
> DaveC
> m...@bogusdomain.net
> This is an invalid return address
> Please reply in the news group
| |
| The Great Attractor 2007-05-10, 3:25 am |
| On 9 May 2007 18:27:43 -0700, MooseFET <kensmith@rahul.net> wrote:
> counterfactual statements
That is your specialty, you retarded fuckhead.
| |
| The Great Attractor 2007-05-10, 3:25 am |
| On Thu, 10 May 2007 01:31:50 GMT, "Michael A. Terrell"
<mike.terrell@earthlink.net> wrote:
>MooseFET wrote:
>
>
> How about a simple warning post, once a week about the losers who
>spread false and dangerous info?
This Terrell asswipe talking about taking folks to court with his
fucking lawyers, yet he feels it fine to post libelous remarks about
anyone he wishes.
Care to post ANYTHING I EVER said that was dangerous, asswipe?
| |
| The Great Attractor 2007-05-10, 3:25 am |
| On 9 May 2007 18:47:13 -0700, MooseFET <kensmith@rahul.net> wrote:
>It worked moderately well. From time to time a newby would jump in
>with a post before reading it and get gently roasted over the open
>flames.
Totally retarded behavior.
Not surprising that you endorse such utter stupidity.
| |
|
|
| Robert Latest 2007-05-10, 3:25 am |
| ["Followup-To:" header set to sci.electronics.design.]
John Larkin wrote:
> OK, positively the last time:
>
> IF THE EMISSIVITY IS 0.98, IT CAN'T BE REFLECTIVE IN THE THERMAL IR.
>
> And while you're at it, check your own link for the emissivity of
> glass. And smooth ice.
He's proven himself to be both stupid and illiterate, so please be nice and
stop riling him by shoving his nose at documents that he can neither read
nor understand.
robert
| |
| David L. Jones 2007-05-10, 3:25 am |
| On May 9, 12:56 am, DaveC <m...@privacy.net> wrote:
> I know this subject of "cheap" and "calibrate" used in the same sentence may
> well be anathema to some of you but I need to verify that either my IR temp | | |