Re : EIT 90

[tinnitus]

hello,

I know this not a labview question but i think many of you have to use this reference.

The trouble i have is where to find documents relative to pt100 calibration  documentation up to date ?

i have formulae, now i want  to test if i haven't done mistakes manupulating all of coefficients

i'm looking for table of DIN 60751/A2  with 0.1° C accuracy between at least between -60 +60°C

and the same for EIT90 calibration with 3 reference points ie : water, gallium ....

Thank you

Best regards

Tinnitus 

[tinnitus]

hello,

i found a table for 3 reference points calibration i just miss DIN 60751/a2  table

regards

Tinnitus

[Eric.M]

Hello Tinnitus,

after a few research, I came across 2 documents, and especially one interesting one on your calibration issue. It seems like Swiss people got an accuracy as good as 0.02K with the DIN 60751 :

PT100 Calibration

I'm pretty sure you're french, so I guess that the pdf language won't be a problem for you.

Regards~

[tinnitus]

Hello,

Thanks for your reply but i already got this table accuracy of method is less than 0.02K but  table is only 1°C .

As i have differences of 0.1 °C with some values  for example with   157.33 ohm my code return 150,01305206°C

  and table indicate 150°C.

So  i would like to confirm with an external document.

Regards

Tinnitus

[Henrik_Volkers]

for example with   157.33 ohm my code return 150,01305206°C

  and table indicate 150°C.

Well, take 150°C you get 157.32513.... Ohm that will round up to 157.33 😉

The standards (as far as I remember) only define the T->R function and that how you can get the resolution you need.

Do you have a standard better than 20mK??  Then you will get R_0, A,B(,C) for this standard and the only truth you know is the T->R function to check against.

I remember programming a Newton zero interation  to 0.1mK resolution for the R->T back in LV3.1 (and Excel) for my final thesis in a calibration lab.....

I only had a draft of the 'new' standard including the brand new ITS90 at that time. One of the draft translations had a minor error in the Type K EMV->T formulas , so I got in contact with the PTB .... 

(guess where I work know 😉 , however not  in the field of temperature )

But I would encourage you to contact your NMI (LNE?) and ask them 🙂 

[tinnitus]

Thanks for reply

standard used is 5187SA  accuracy is +-0.001°C

yes i saw that , i also use the newton methode to calculate T°

I just want to be sure not making error  converting R->T and T->R  just

because of code .  i have already enough sources of error that adds and adds.......

Regards

Tinnitus

[Henrik_Volkers]

---

standard used is 5187SA  accuracy is +-0.001°C

---

1mK is the increase of your sensor reading by radiation , when the sensor is hanging in the corner of  a room (20°C) and you enter it 😉

I remember having problems getting u<5mK in a stirred liquid bath.....

What do use for reading? a Paar?

[tinnitus]

not a Parr

an asl 17A  or an isotech uK 800 bridge

Tinnitus

[tinnitus]

hello,

always woking on platinum probes

i don't find information about pt25 and pt1000

Could i use same coefficients as pt100 for or there are disctincts ?

Best regards

Tinnitus

[Henrik_Volkers · Accepted solution]

If not individually calibrated, use standard  A,B and C and change R_o to 25, 1000 or whatever value you find at 0°C  (a linear approximation to 0°C while using a water tripplepoint cell  (0.01°C) seems to be valid 😉 )   That's the nice thing about the (simplified) Callendar van Dusen Formular.