Author Topic: High precision thermocouple scanners?  (Read 848 times)

0 Members and 1 Guest are viewing this topic.

Offline mzzj

  • Super Contributor
  • ***
  • Posts: 1078
  • Country: fi
High precision thermocouple scanners?
« on: October 16, 2021, 03:54:09 pm »
Got any hints on "metrology grade" thermocouple scanners?
Looking for something like 16+ channels, built-in CJC with 0.1...0.2 Cel accuracy.

CJC accuracy is usually the weak link in "general purpose" scanners like Keysight 34970A.
AFAIK 34970A CJC specification is something like 0.8Cel and it's not performing any better in real life  :P
 

Offline 3roomlab

  • Frequent Contributor
  • **
  • Posts: 835
  • Country: 00
  • kT kT kT kT kT kT kT kT kT
a human being is like a 80w lamp heat source walking around a precision lab, sheds about 20g of water an hour on all the precision electronics around him/her. If a precision instrument has a voice, it would say get away from me you #@$%#$^ .
 

Offline voltsandjolts

  • Supporter
  • ****
  • Posts: 1438
  • Country: gb
Re: High precision thermocouple scanners?
« Reply #2 on: October 16, 2021, 05:46:45 pm »
34970A + PT100
 

Offline bck

  • Contributor
  • Posts: 12
  • Country: de
Re: High precision thermocouple scanners?
« Reply #3 on: October 16, 2021, 05:52:09 pm »
Additel ADT 286

datasheet is attached
CJC Accuracy is 0.1C
~ Alexander Becker
 
The following users thanked this post: mzzj

Offline mzzj

  • Super Contributor
  • ***
  • Posts: 1078
  • Country: fi
Re: High precision thermocouple scanners?
« Reply #4 on: October 16, 2021, 05:57:43 pm »
search for "scanner"

Didn't see anything specific to my task. I'm looking for thermocouple scanner, not just low thermal EMF scanner.
 

Offline mzzj

  • Super Contributor
  • ***
  • Posts: 1078
  • Country: fi
Re: High precision thermocouple scanners?
« Reply #5 on: October 16, 2021, 06:05:31 pm »
Additel ADT 286

datasheet is attached
CJC Accuracy is 0.1C
!
Now we are getting somewhere.
Actually really good looking unit for temperature cal laboratory with 1 ppm resistance ratio measurement and 8½ digit DMM in one package.

Additel didn't even cross my mind so this was exellent tip. (was familiar with their pressure equipment and dry blocks)
« Last Edit: October 16, 2021, 06:07:09 pm by mzzj »
 
The following users thanked this post: bck

Offline 2N3055

  • Super Contributor
  • ***
  • Posts: 4166
  • Country: hr
Re: High precision thermocouple scanners?
« Reply #6 on: October 16, 2021, 09:14:58 pm »
https://www.aoip.com/product/benchtop-measurement-and-calibration-instruments/microk-3/

not 16 ch though..

EDIT:
was remembering/looking  wrong.. It can be expanded up to 92 channels..
« Last Edit: October 17, 2021, 09:15:18 am by 2N3055 »
 

Offline miro123

  • Contributor
  • Posts: 42
  • Country: nl
Re: High precision thermocouple scanners?
« Reply #7 on: October 16, 2021, 09:24:54 pm »
34970A + PT100
+1 - I think also that PRT or SPRT is the way to go.
https://us.flukecal.com/products/temperature-calibration/its-90-temperature-standards/standard-platinum-resistance-thermomet

I have several  questions  to the topic starter
1. What is your application?
2. there are many methods for temperature sensing -   /contact and non-contact/. Do you use the right one for your application
3. What is the temperature accuracy of termocouple itself?
4. How big is the system error of temperature measurement? e.g. contact effect etc.

I asking this questions because I want to have clear picture of our measurement setup.
PS I have similar experience with HP3497A and thermocouples ~1degree, but that is enought. Most termocouples have higher error than TCJ
« Last Edit: October 16, 2021, 10:07:54 pm by miro123 »
 

Offline mzzj

  • Super Contributor
  • ***
  • Posts: 1078
  • Country: fi
Re: High precision thermocouple scanners?
« Reply #8 on: October 17, 2021, 03:50:50 am »
34970A + PT100
+1 - I think also that PRT or SPRT is the way to go.
https://us.flukecal.com/products/temperature-calibration/its-90-temperature-standards/standard-platinum-resistance-thermomet

I have several  questions  to the topic starter
1. What is your application?
2. there are many methods for temperature sensing -   /contact and non-contact/. Do you use the right one for your application
3. What is the temperature accuracy of termocouple itself?
4. How big is the system error of temperature measurement? e.g. contact effect etc.

I asking this questions because I want to have clear picture of our measurement setup.
PS I have similar experience with HP3497A and thermocouples ~1degree, but that is enought. Most termocouples have higher error than TCJ
Too many questions and few answers  ;)

1. Temperature Cal lab UUT readout or data logging for temperature surveys.
2. Yes.
3. After initial calibration and calculating the correction factors T-type thermocouple is accurate to about 0,05 cel.
(NPL calibrated Pt-Au thermocouple is 0,05 degrees! up to 1000 cel and gives good run for your money compared to HTSPRT. )
4. Depends on case but I don’t want to get drifted too far. Lets imagine we have SPRT+ASL F900 in calibration bath.  ;)

« Last Edit: October 17, 2021, 03:52:42 am by mzzj »
 

Offline LaserEng

  • Regular Contributor
  • *
  • Posts: 57
  • Country: th
Re: High precision thermocouple scanners?
« Reply #9 on: October 17, 2021, 06:29:32 am »
I doubt you could get much better than Isotech's temperature measuring equipment, a MicroK plus a 90 channel expander.

Microk
https://isotech.co.uk/products/microk-precision-thermometry-bridge/

Expander
https://isotech.co.uk/products/microk-channel-expander/

Maybe this whitepaper about cold junction compensation and using a double junction thermocouple will be of interest

https://isotech.co.uk/wp-content/uploads/2020/09/Double-Junction-Thermocouple-Part-1-1.pdf
https://isotech.co.uk/wp-content/uploads/2020/09/Double-Junction-Thermocouple-Part-2-1.pdf
 

Offline 2N3055

  • Super Contributor
  • ***
  • Posts: 4166
  • Country: hr
Re: High precision thermocouple scanners?
« Reply #10 on: October 17, 2021, 09:13:56 am »
I doubt you could get much better than Isotech's temperature measuring equipment, a MicroK plus a 90 channel expander.

Microk
https://isotech.co.uk/products/microk-precision-thermometry-bridge/

Expander
https://isotech.co.uk/products/microk-channel-expander/

Yep, that's AOIP I linked to..

Those are primary lab instruments..
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf