Questions on pt100 probes

[Sensorcat]

Sensorcat
You know, you made a trivial mistake then. The ice is supposed to be moist/moistened and not swim in "cold water". Water has the highest density at 4 degrees Celsius. This causes ice to "dribble to the bottom of the vessel", while ice has a lower density at approximately 0 degrees Celsius, so it "floats". This is one of the reasons why fish survive in lakes in winter. The ice in the thermos must be constantly "drained" of excess water - this is NECESSARY in such an implementation. The sensor is not meant to be "pushed to the very bottom of the vessel". The sensor is to be in the "middle part of the snow block" - pressed.
There is a very nice pdf explaining how to do this on the New Zeland National Laboratory website.

Although you should not think that my own experiments involved a single icecube floating on water, I do know now, thanks to the valuable resources posted by mzzj, that the ice bath has to meet harder requirements with little tolerance (for instance, having small pieces of ice). That's why I prefer to see this as difficult, not as easy, which was the first point I wanted to make in this thread. Murphy is my witness that it is preferable to see tasks as difficult rather than easy, if you want to achieve stable and reliable results. Note that I never claimed that I know how to prepare a good ice bath, so I did not make 'a trivial mistake.'

And this leads to my second point: If you need reliablity, you need a process. A process makes all relevant factors explicit, not implicit, and avoids the human factor. Standards that have to do with assurance of quality or safety therefore involve auditing, with the auditor always asking one question, in endless variations: 'How do you make sure that ...?' And if you reply 'I know that.' - 'It's easy.' - 'Never has been a problem.' you should not get your certificate (provided that the auditor does his job properly), because that's not a process. And having a process is certainly not limited to technology with the highest requirements! Whenever not meeting requirements (tight or loose) has dire consequences, you need a process. Who does not understand this should not think of designing something serious, because if you do anyway, things like this happen:
https://www.eevblog.com/forum/chat/baltimore-francis-scott-key-bridge-collapse/

[MiDi]

Sensorcat
There is a very nice pdf explaining how to do this on the New Zeland National Laboratory website.

Standards Lab NZ Document

[Yuu]

Does anyone have a title for whatever this Nicholas & White 2001 paper/text is?

I'm interested how they derive their "polishing function." It doesn't appear to be some newton root finding method.

Edit: found it
Nicholas J V and White D R (2001) Traceable Temperatures: An Introduction to
Temperature Measurement and Calibration (John Wiley and Sons, Chichester).

[mendip_discovery]

Traceable Temperatures, produced by Wiley.

Physical copies are hard to come by.

[arvee]

Hi,

Fluke has a webpage for the PT100 https://us.flukecal.com/pt100-calculator

Here is my calculator in HTML.

Details of the Newton root iteration be found in the comments of the calculator.

RV

[BarrowBoy]

Here I go again. Newbie, 10th post. Very addictive forum. Love Temperature discipline, but again not typical hands on, although I know and am trained in creating a TPW, and I don't mean making one from scatch...lol. I mean the process of creating the all important ice mantle within the TP cell. Try making one....your first skill is to learn  glassblowing, and bonding dissimilar glasses.

If range is 0-100C, then any reason a Thermistor is not being used? They have a far greater value change across their working range and are very good in this temperature range IMO. Below is something I found online which is a good summary of why I ask.

[BarrowBoy]

NIST, BIPM and NZ national standards labs have some good guides:
https://www.measurement.govt.nz/resources/#collapse-control-1-5
https://nvlpubs.nist.gov/nistpubs/Legacy/TN/nbstechnicalnote1411.pdf
https://www.bipm.org/documents/20126/41773843/Specialized-FPs-above-0C.pdf/10265617-c79f-0ea5-8da9-8d359e21c6be



If I needed to verify the ice bath I have 3 resistance bridges, 5 triple point cells and close to dozen SPRT's at my disposal.
But if the ice bath is prepped according to above guides I'd suspect anything else before the ice bath. Haven't seen ice bath deviate more than 0.003C in my career if it is prepped properly.

Thank you for posting these.along with gravity.

Gee, you have got the gear to confirm your claims...lol. One thing I'd mention here is purity of water, can be a key consideration when best practices need to be employed. Some would agree that's all the time, others only as deemed necessary.