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Best portable multichannel thermocouple thermometer

P

Phil Hobbs

Jan 1, 1970
0
Hi, all,

One of my gizmos that I transferred to a contract engineering outfit in
Orange County CA is having a few teething troubles, which my original
prototype didn't exhibit. I suspect that it's largely due to thermal
drift, either in the circuitry, the light source or the alignment.

To test this, I need to get a thermocouple thermometer that is good and
rugged, can measure at least two channels and preferably four, and is as
accurate as you can reasonably do with a thermocouple, maybe 0.25 to 0.5
degrees C. The temperature range is maybe 0 to 100 C. Extra credit for
isolated channels, and for being able to go to 250C so I can measure the
bulb envelope temperature, at least at some level.

Budget is probably $500.

Suggestions?

Thanks

Phil Hobbs


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net
 
L

Lasse Langwadt Christensen

Jan 1, 1970
0
Den tirsdag den 31. december 2013 02.16.32 UTC+1 skrev Phil Hobbs:
Hi, all,



One of my gizmos that I transferred to a contract engineering outfit in

Orange County CA is having a few teething troubles, which my original

prototype didn't exhibit. I suspect that it's largely due to thermal

drift, either in the circuitry, the light source or the alignment.



To test this, I need to get a thermocouple thermometer that is good and

rugged, can measure at least two channels and preferably four, and is as

accurate as you can reasonably do with a thermocouple, maybe 0.25 to 0.5

degrees C. The temperature range is maybe 0 to 100 C. Extra credit for

isolated channels, and for being able to go to 250C so I can measure the

bulb envelope temperature, at least at some level.



Budget is probably $500.



Suggestions?

fluke 52 or fluke 54 ?

dual channel and I think ~$300/~$400


-Lasse
 
M

Martin Riddle

Jan 1, 1970
0
Hi, all,

One of my gizmos that I transferred to a contract engineering outfit in
Orange County CA is having a few teething troubles, which my original
prototype didn't exhibit. I suspect that it's largely due to thermal
drift, either in the circuitry, the light source or the alignment.

To test this, I need to get a thermocouple thermometer that is good and
rugged, can measure at least two channels and preferably four, and is as
accurate as you can reasonably do with a thermocouple, maybe 0.25 to 0.5
degrees C. The temperature range is maybe 0 to 100 C. Extra credit for
isolated channels, and for being able to go to 250C so I can measure the
bulb envelope temperature, at least at some level.

Budget is probably $500.

Suggestions?

Thanks

Phil Hobbs

Some two channel J K T H E loggers...
<http://www.coleparmer.com/Product/Simple_Logger_II_Thermocouple_Model_L642/EW-26060-13>
+/- 0.6 to 1 deg F?

Maybe you need a silicon bandgap temp sensor?


Cheers
 
M

Maynard A. Philbrook Jr.

Jan 1, 1970
0
Hi, all,

One of my gizmos that I transferred to a contract engineering outfit in
Orange County CA is having a few teething troubles, which my original
prototype didn't exhibit. I suspect that it's largely due to thermal
drift, either in the circuitry, the light source or the alignment.

To test this, I need to get a thermocouple thermometer that is good and
rugged, can measure at least two channels and preferably four, and is as
accurate as you can reasonably do with a thermocouple, maybe 0.25 to 0.5
degrees C. The temperature range is maybe 0 to 100 C. Extra credit for
isolated channels, and for being able to go to 250C so I can measure the
bulb envelope temperature, at least at some level.

Budget is probably $500.

Suggestions?

Thanks

Phil Hobbs

http://www.extech.com/instruments/product.asp?catid=64&prodid=626

That's your best deal there I think, it gives you SD card for recording
and it has a long data-logging run time.

That comes with 3 channels with K probes, etc..

Jamie
 
M

miso

Jan 1, 1970
0
So how did you temperature test it in the first place?

I've never cranked a test oven that high. Probably the max I ever did
was 170 deg C testing thermal shutdown.
 
P

Paul E Bennett

Jan 1, 1970
0
Phil said:
Hi, all,

One of my gizmos that I transferred to a contract engineering outfit in
Orange County CA is having a few teething troubles, which my original
prototype didn't exhibit. I suspect that it's largely due to thermal
drift, either in the circuitry, the light source or the alignment.

To test this, I need to get a thermocouple thermometer that is good and
rugged, can measure at least two channels and preferably four, and is as
accurate as you can reasonably do with a thermocouple, maybe 0.25 to 0.5
degrees C. The temperature range is maybe 0 to 100 C. Extra credit for
isolated channels, and for being able to go to 250C so I can measure the
bulb envelope temperature, at least at some level.

Budget is probably $500.

Suggestions?

Thanks

Phil Hobbs
The Pico Thermocouple data logger is good and has moree than two channels.
Comes with software and connects to the PC via USB. About half your budget
level I should think. Last we used this was with a small experiement that
was monitoring thermal transfer between two metal components in a high power
scanning electron microscope. As the experiement started melting one of the
metal components and the readings were still coming I think your range is
well within its capabilities.

<http://www.picotech.com/thermocouple.html>

--
********************************************************************
Paul E. Bennett IEng MIET.....<email://[email protected]>
Forth based HIDECS Consultancy.............<http://www.hidecs.co.uk>
Mob: +44 (0)7811-639972
Tel: +44 (0)1235-510979
Going Forth Safely ..... EBA. www.electric-boat-association.org.uk..
********************************************************************
 
Phil Hobbs said:
To test this, I need to get a thermocouple thermometer that is good
and rugged, can measure at least two channels and preferably four, and
is as accurate as you can reasonably do with a thermocouple, maybe
0.25 to 0.5 degrees C. The temperature range is maybe 0 to 100 C.
[...]
Budget is probably $500.

Suggestions?

Omega does a lot of temperature stuff and seems to be reasonable about
having things in stock. I have used their handheld meters and
thermocouples before in a portable application (college engineering lab
stuff) and they worked OK, but the requirements there (+/- 1 C or so,
single channel) weren't as tight as yours. I also used one of their
bench-type meters - really an industrial panel meter in a box - with
thermocouples at work for product testing (+/- 1 C or so, multiple
channels) and it worked OK.

Looking at their online catalog... HH501DK. 4 channels, Type K,
"±(0.3% rdg + 1°C) -50 to 1000°C". No mention of isolation. It even
comes with four simple Type K thermocouples and a battery, for $125.
http://www.omega.com/pptst/HH501DK.html

HH147U. 4 channels, Type K plus others, "±(0.1% rdg + 0.7°C) -100 to
1300°C" for Type K. It will log data to internal memory and download
it via USB. No mention of isolation. It comes with Windows software,
one simple Type K thermocouple, and batteries, for $300.

RDXL4SD. 4 channels, Type K plus others, "-50.1 to -999.9ºC
±(0.4% + 1ºC)" for Type K. (I think that's a misprint and should
really be -50.1 to +999.9 C.) It logs data to an SD card and also
has a USB connection, but the Windows software is apparently separate
at $100. No mention of isolation. It comes with a 2 GB SD card, no
batteries (6 AA) or thermocouples, for $300.

There are some other models that may fit the bill, including HH1384
($375), HH309A ($315), HH374 ($300), and HH378 ($340).
http://www.omega.com/pptst/HH1384.html
http://www.omega.com/pptst/HH309A.html
http://www.omega.com/pptst/HH374.html
http://www.omega.com/pptst/HH378.html

This may be in the "grandmothers and eggs" category, but one thing I
have found, with any portable thermocouple application, is that the
screws inside the thermocouple connectors at the meter end tend to
loosen up as things are banged around. A lot of meters can tell if the
thermocouple is completely open circuit, but I have found that they
can't detect slightly-loose screws that give unstable readings. One
way I have found this problem is to put the thermocouple junction in a
place where the temperature should be pretty stable, and then tap and
tug on the connector with my fingers.

Standard disclaimers apply: I don't get money or other consideration
from any companies mentioned.

Matt Roberds
 
S

Spehro Pefhany

Jan 1, 1970
0
Hi, all,

One of my gizmos that I transferred to a contract engineering outfit in
Orange County CA is having a few teething troubles, which my original
prototype didn't exhibit. I suspect that it's largely due to thermal
drift, either in the circuitry, the light source or the alignment.

To test this, I need to get a thermocouple thermometer that is good and
rugged, can measure at least two channels and preferably four, and is as
accurate as you can reasonably do with a thermocouple, maybe 0.25 to 0.5
degrees C. The temperature range is maybe 0 to 100 C. Extra credit for
isolated channels, and for being able to go to 250C so I can measure the
bulb envelope temperature, at least at some level.

Budget is probably $500.

Suggestions?

Thanks

Phil Hobbs

If you were willing to use RTDs, something like an Adam 6015
(Advantech) would handle 7 channels, have 10/100 Ethernet interface,
and fits your price budget. No display, but I think they have free
software for viewing the readings on a netbook or whatever.

Accuracy should be considerably better than T/C over that range,
particularly if the ambient temperature is not closely regulated.


Best regards,
Spehro Pefhany
 
A

Artem

Jan 1, 1970
0
If you were willing to use RTDs, something like an Adam 6015

(Advantech) would handle 7 channels, have 10/100 Ethernet interface,

and fits your price budget. No display, but I think they have free

software for viewing the readings on a netbook or whatever.

Any free Modbus/TCP software.

Or maybe only web browser will be necessary.
 
G

George Herold

Jan 1, 1970
0
Hi, all,

One of my gizmos that I transferred to a contract engineering outfit in
Orange County CA is having a few teething troubles, which my original
prototype didn't exhibit. I suspect that it's largely due to thermal
drift, either in the circuitry, the light source or the alignment.

To test this, I need to get a thermocouple thermometer that is good and
rugged, can measure at least two channels and preferably four, and is as
accurate as you can reasonably do with a thermocouple, maybe 0.25 to 0.5
degrees C. The temperature range is maybe 0 to 100 C. Extra credit for
isolated channels, and for being able to go to 250C so I can measure the
bulb envelope temperature, at least at some level.


Budget is probably $500.


Suggestions?
None, (sorry) But I'm interested in what others offer.
One issue I found with a cheap omega (panel mount) was that the cold junction temp sensor seemed to be on the opposite end of the pcb from the TC input.
I guess not that much of an issue if you mostly care about relative temps and not absolute.
(I can send a bucketful* of pnp's in to-220 packs that are calibrated to ~0.3C from 77K to 400K.. with most of the uncertainty at the low temp end.)
https://www.dropbox.com/s/gtrgm08ui2lre78/Diode calibration table.doc

George H.
* well ok not a bucket full... I have to do a single point room temp measurement on each one...but 2-3 is easy.
 
R

RobertMacy

Jan 1, 1970
0
As I said, "bulb envelope temperature". One of those retro tungsten
things that emits from the far IR to the near UV, not a circuit board.

Cheers

Phil Hobbs

With a thermocouple mounted on the envelope and at that close aproximity,
wouldn't radiation effects get into play?
 
P

Phil Hobbs

Jan 1, 1970
0
With a thermocouple mounted on the envelope and at that close
aproximity, wouldn't radiation effects get into play?

Sure. What I'm trying to track down is a DC drift problem in a chopped
AC measurement. One of those effects you don't usually think about too
much is the effect of ambient temperature on bulb output.

If you take a tungsten bulb at constant input power, and raise its
ambient temperature by 10 degrees, the filament will get hotter by
probably 2 or 3 degrees, so it gets a bit brighter. The thermocouple
will see both effects, but it'll at least allow me to estimate whether
they're plausible causes.

It's a fibre-bundle spectrometer, so there are other possible issues,
e.g. mechanical drift plus a moire pattern between the fibre ends and
the image of the helical filament. The particular bulb has a box-wound
filament, and is canted a few degrees so that the wire in the back of
the helix fills in the spaces in the front, but there could still be
some residual effect.

The first thing you look for in debugging thermal problems in an
optomechanical system is bending due to temperature gradients or
dissimilar CTEs.

My original prototype was built open-style, using Microbench optical
rails and an RC-airplane servo motor for turning the grating, with a
CMOS mux as the phase detector and a LabJack U6Pro for data acquisition.
The new swoopy one has a very nice 3D-printed case, a proper encoder
on the shaft, and an all-digital back end.

But it drifts, and mine didn't (despite being made of toy parts and
dead-bug circuitry). We're going to spend next week going through it in
the goriest possible detail, because I have no interest whatsoever in
doing it over again.

Cheers

Phil Hobbs



--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net
 
M

miso

Jan 1, 1970
0
Ovens are pretty cheap on the surplus market if you only want heat.
Cooling takes forever without the nitrogen tank.

I've had bad luck with refrigerated test chambers as far as reliability
goes, but much less condensation during cold testing than with that
nitrogen blaster. I do know someone that swears by Thermotron test
chambers. Not to be confuser with the old Thermostream by Temptronic,
AKA the cone of silence chamber.
 
F

Fred Abse

Jan 1, 1970
0
[quoted text muted]

http://www.extech.com/instruments/product.asp?catid=64&prodid=626

That's your best deal there I think, it gives you SD card for recording
and it has a long data-logging run time.

That comes with 3 channels with K probes, etc..

Do you have any experience with those? I have a job coming up requiring
monitoring of multiple temperatures. The Extech looks attractive, and the
price is right on the money. Thermocouple accuracy is fine.

I'd appreciate any comments you might have.
 
M

Maynard A. Philbrook Jr.

Jan 1, 1970
0
Do you have any experience with those? I have a job coming up requiring
monitoring of multiple temperatures. The Extech looks attractive, and the
price is right on the money. Thermocouple accuracy is fine.

I'd appreciate any comments you might have.

I don't have that unit but we have a visiting tech for a specific
machine that is rented and he swears by it. He has left it at out place
a couple times to do long data logs.

I do have some Extech gear myself, one of them has a K-probe and IR
probe on it. I would not trust the IR probe so much but the K-probe is
very accurate. That meter has been dropped, bagged around and it still
working.

I also have an Agilent K-probe meter but at times I question that.

Jamie
 
F

Fred Abse

Jan 1, 1970
0
I don't have that unit but we have a visiting tech for a specific
machine that is rented and he swears by it. He has left it at out place a
couple times to do long data logs.

I do have some Extech gear myself, one of them has a K-probe and IR
probe on it. I would not trust the IR probe so much but the K-probe is
very accurate. That meter has been dropped, bagged around and it still
working.

I also have an Agilent K-probe meter but at times I question that.

Thanks
 
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