Talk:Resistance thermometer

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Hi, I'm new here and don't know much. But I got here when refurbishing a pair of Hart 1006 thermometers and I needed the R vs. T values from your table. Thank you for those. I have a couple of questions: 1. What does "Typ" refer to in the table? Is this short for Type? I tried googling for an answer and didn't see much. Is there some kind of standard type designators?

2. I ran across the publication "NIST Special Publication 250-81" by Strouse, 2008. It seems like an important paper that lays down the accepted wisdom, but I don't see it in the references on this page. Should it be? Just asking.

Thanks again for all of your efforts on this page! Yankeepapa13 (talk) 21:52, 6 December 2015 (UTC)

what's the difference between a resistance thermometer and a Thermistor? Weedwacker 203.214.123.115 (talk) 12:44, 11 May 2008 (UTC)

From the thermistor page: Thermistors differ from resistance temperature detectors (RTD) in that the material used in a thermistor is generally a ceramic or polymer, while RTDs use pure metals. The temperature response is also different; RTDs are useful over larger temperature ranges, while thermistors typically achieve a higher precision within a limited temperature range. Thermistors are also more subject to self-heating effects than resistance thermometers. Spuzzdawg (talk) 20:45, 25 February 2009 (UTC) —Preceding unsigned comment added by 168.132.121.146 (talk)

The reference to "alpha" in the "Temperature to resistance equation" section does not connect. Where is alpha? Torsionalmetric (talk) 13:50, 10 July 2008 (UTC)

Untitled 2
Even metal clad RTD are easily broken when subjected to physical shock or distortion (flexing). Sponsion (talk) 14:30, 25 June 2010 (UTC)

Untitled 3
I would prefer if we dropped the lower case "s" and refer to "RTD" in the singular. When writing "RTD" in technical papers, the "s" is inherent or implied within RTD and is therefore redundant.

E.g., "RTDs resistance change are relatively linear over extensive temperature ranges." This may be written as "RTD resistance change is relatively linear over extensive temperature ranges."

If no one objects, I will eventually edit the article to remove the lower case "s"; i.e., I will change (RTDs) to (RTD) and correct the subject verb agreement. Sponsion (talk) 14:30, 25 June 2010 (UTC)

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The resistance value for the PT100 RTD at T=55C appears to be an outlier. The value listed in the table is 121.49, but a value of 121.32 would fall closer to the curve described by the other values. — Preceding unsigned comment added by 108.7.96.172 (talk) 22:13, 4 August 2012 (UTC)

Resistance thermometer vs platinum resistance thermometer
This article needs to be either renamed or updated to include thermistors. A thermistor IS a resistance thermometer. Moreover, there are more thermistors produced and used commercially than either PRTs or thermocouples.

Perhaps the article should be renamed as "Platinum resistance thermometer", especially as other RTD types (most notable is nickel) are also omitted. 71.228.106.24 (talk) 19:59, 11 July 2010 (UTC)

Wiring configurations
The section "Wiring configurations" contains completely useless information. Do not confuse the 2-, 3-, 4-wire resistance measurements with the Wheatstone bridge measurement! The allowable cabling length that you mention is wrong! Nobody applies 3 wire configuration for example the length of 500 m. For this length use a transmitter!

Please correct your article, because the "Wiring configurations" section is completely wrong! — Preceding unsigned comment added by 82.131.179.39 (talk) 05:27, 13 May 2013 (UTC)
 * I agree! This section lags a reference. I guess, it's a copy from http://www.thermometricscorp.com/rtd.html (click 2-, 3-, 4-Wire RTD) without citation, or the other way around. Also, the wire configurations shown are very weird. While the 2- and 3- wire configuration are pretty common, I don't see any reason to use one of the 4-wire configurations. The first one is just like the 3-wire configuration, but with double wire influence. I tested the second configuration using LTSpice and it's not zeroing the wire influence as stated in the text. Also, wiring of resistive sensors is not specific to RTDs. I think, the whole section should be deleted.Laubeg (talk) 16:01, 15 July 2014 (UTC)
 * The German article contains a better wiring-section ([]).Laubeg (talk) 16:16, 15 July 2014 (UTC)

I disagree with user 82.131.179.39, this section is important as it is not obvious how to use a 3 wire configuration. Unfortunately the wiring for the 3 wire configuration is wrong (as are 99% of the web articles/pictures) which is why it doesn't work in LTSpice ( guess everyone has copied this article! A correct version can be viewed at http://www.ni.com/white-paper/14853/en/ . The double wires are to be connected to ground and the left leg of the bridge, the single wire attaches to R1/bridge output. The original has (r1+lr)/(rt+lr) as the left ratio and r2/r3 as the right which works only if r1==r2==r3~=rt. The correct version should be r1/(rt+lr) and the right r2/(r3+lr) keeping the bridge balanced regardless of value of lr (lead resistance), but does not compensate for variation of resistance in the wires. The four wire interface works "perfectly" as the 2 sense wires carry no current and hence no error, but the measurement is more complicated as you are measuring the complete resistance not just it's offset from R3. 24.246.5.185 (talk) 02:04, 29 September 2015 (UTC)

Attribution of strain gauge behavior to thin film RTD in Element types section
The strain gauge effect is orders of magnitude below the effects of phonon scattering. Thin film RTDs are less stable because there is less platinum material so they are more susceptible to contamination. This can be mitigated by good packaging. Tennesteve (talk) 03:05, 11 July 2013 (UTC) comment added by Tennesteve (talk • contribs) 02:58, 11 July 2013 (UTC)Tennesteve (talk) 03:05, 11 July 2013 (UTC)

Wiring configuration 2
In the diagram for your 3-wire configuration, you have the sense wire leading to the Galvanometer as being one of the lead wires. This is wrong - it is the wire just above it that is the lead wire. — Preceding unsigned comment added by 176.74.250.17 (talk) 11:21, 2 October 2013 (UTC)

sensitivity at Very Low Temperatures
well, the article says "At very low temperatures, say below -270 °C (or 3 K), because there are very few phonons, the resistance of an RTD is mainly determined by impurities and boundary scattering and thus basically independent of temperature. As a result, the sensitivity of the RTD is essentially zero and therefore not useful." Is "sensitivity" the same as "accuracy"?

And what of the range itself, below 3 kelvin? Is that important, because it is so narrow? (0-3 K)

Mang (talk) 23:23, 5 November 2013 (UTC)

contradiction
At the moment, one part of this article says "calibration must be performed at temperatures other than 0 °C and 100 °C." and another part says "A common fixed point calibration method for industrial-grade probes is the ice bath."

How is it possible that calibration at 0 °C is "common", and also that calibration must be performed at some temperature other than 0 °C ?

It also seems contradictory to list two calibration methods and to say of one of them "This method might be more cost-effective since several sensors can be calibrated simultaneously", while saying of the other one "The equipment is inexpensive ... and can accommodate several sensors at once."

How can "several sensors ... simultaneously" be the reason one method costs less than the other method, when it is true of both methods?

How can we improve this article to be less self-contradictory? --DavidCary (talk) 04:15, 21 July 2014 (UTC)


 * Hello David,

I can see that there are few anomalies in the article, and would be happy to assist you in any of your queries. However, the reason of the stated contra are as follows:

Most of the contradication has come due to the fact that editors of the article has taken specific extracts from the Author John G. Webster's book The Measurement, Instrumentation and Sensors Handbook -> isbn=0849383471. There the relative temperatures and its use is defined with a different accuracy level, delving more into the calibrative measurement, rather than the temperate measurements.

1. When we say the ice bath, it speciafically states the resistance start level of the prode. Also, a common obvusive range is always -0.02°C to +0.03°C (a range of 0.05°C of +-). 2. When you calibrate simultaneously, the result is always a best one, and the sensors are at their 99.9897596% claibration level (the rest 0.0102404% being the calibrated error range). 3. The equipment is truly inexpensive, as it can accomodate several or many sensors to be calibrated at one point, but there is always a error sequence of more than +-5, which can range between a fluctuating +-6-8. This is a very high level of error, as compared to some normal level of tempratures. When I say very high, I mean that for linear temperatures, and for a specific range of calibrative measures, the range can turn the production into a different output frame, and can make the output a bad one, or can stop the process altogether. (These outputs are based on the relative set and process values, which can get effected due to a claibrative error, again depending).

In case you require any assistance, I will be happy to assist you. Jai Jinendra. Vishal Bakhai - Works 11:01, 29 July 2014 (UTC)

Dear Vishal and other Wikipedia editors,

I find the "99.9897596%" and "0.0102404%" numbers surprising, and I don't understand what they mean. Can you help me find a reference -- a book or a web page -- that explains them? Also, the "error sequence of more than +-5 ... fluctuating +-6-8." Can you help me find a reference -- a book or a web page -- that explains that?

The article seems to be describing two different kinds of calibration equipment. The comment that "The equipment is truly inexpensive" is ambiguous. Does that mean that "fixed point calibration equipment is inexpensive", or "comparison calibration equipment is inexpensive", or "both are inexpensive"?

How can we improve this article? --DavidCary (talk) 14:57, 29 July 2014 (UTC)
 * Hello again David

As I stated that the reference in the article has been taking with a combination of the following: Author John G. Webster's books -> The Measurement, Instrumentation and Sensors Handbook -> ISBN=0849383471 & The Mechanical Variables Measurement - Solid, Fluid & Thermal -> ISBN=9780849300479.

If you read through the calibration conditions, the stated specifies two types of methods. 1. Two maintain the highest accuracy level, which are set at triple point or conjunction ranges, like that of pure substances, say Water, Argon, etc., These can be achieved with placing the calibration measurement level range at ice bath or isotherm level, which achieves a ±0.001°C results. While the set ice points have a deviance of ±0.005°C, which is highly deviated and can cause a higher range of hysteresis. 2. Unlike the fixed range of 0-100, the second method ranges from -100 till 500, which not only gives a wider range of comparing temperature, but also can conduct different range sensors, like say -100 to +100, or +100 - +400, etc., Also, unlike the fixed range, wherein the number of sensors which can be calibrated are less, the comparison calibration provides various different ranges, and thus assists in keeping the cost of calibration down. Generally, the medium used are molten salt or silica oil.

If you look at this diagram Isotherm, then you will have much clear understanding. The image describes a level at which the calibration is set and the different other levels.

As for the range that I gave, is actually a live example, which I achieved a few days back (I was asked to achieve it in order to conclude a theory), and which is actually not found in books, or websites, as those are accurate figures, and the lineage ranges are rarely mentioned at places.

For the terminology "inexpensive", I would say that the comparison calibration is feasibly less expensive than fixed one. However, the range that the comparison calibrator takes into account is a very high range in negative figures, and thus are rarely found in the open air experiments (as in lab experiments, or regularised). In order for that, the most common factors are taken into consideration, and thus, the accuracy level is determined.

The fluctuating range is the resistance full scale range, which fluctuates till 5 in both positive figures and negative ranges. These are stated to be highly volatile, as the accuracy level is dis-balanced, and can cause lots of difference between the actual range and the reading temperature.

As for improving this article, I believe that it just requires further expansion, and not too much of alterations, as most of the base points described are in layman as well as technical language, and thus is at a good place. Still if you think there is anything which can be made a better read and with better understanding, it will be great. Let me know.

Hope, I have been able to assist you. Still, you can reach out to me anytime. Jai Jinendra. Vishal Bakhai - Works 18:29, 29 July 2014 (UTC)

Article content with WP:CITESPAM removed
The recently removed content contained excessive linking to presentation slides from 1 company, added by an SPA-editor (most likely with a COI for this company). Such content violates WP:CITESPAM and WP:RS, and did also plagiarize the original sources (atleast partially). As far as the content was relevant for this topic, it should be completely rewritten by uninvolved editors and referenced with independent scientific or academic sources. GermanJoe (talk) 00:19, 9 February 2016 (UTC)

Assessment comment
Substituted at 18:34, 17 July 2016 (UTC)

ITS-90 Pt100
On 11 December 2015 there was a column added with values of ITS-90 Pt100, which contains incorrect values. I am not aware of such a thing as ITS-90 Pt100. I did not find any other sources, so i don't consider it popular thermometer. In the cited paper there is nothing about that type. The values are not included in the cited paper. So I assume that this column talks about the ITS-90 reference function for RTPW=100 All pt100 have 100 Ω at 0.00 °C. I assume these values were calculated with RTPW=100, which is wrong for pt100. 100 Ω is at 0.00 °C and not at 0.01 °C. — Preceding unsigned comment added by 62.168.101.66 (talk) 07:44, 16 August 2017 (UTC)

Sources of different temperature coefficients of resistance.
From the article: "These different α values for platinum are achieved by doping – carefully introducing impurities, which become embedded in the lattice structure of the platinum and result in a different R vs. T curve and hence α value.[citation needed]"    My understanding is that the original PRT's were bare Pt wire, wound on a bobbin such that the wire was free to expand with temperature. That gave one temperature coefficient of resistance. Later, PRTs were built with platinum plated on other materials, such as alumina. Since the base material had a different thermal expansion than pure platinum, the the platinum was constrained to mechanically expand to a different degree than a bare, free wire would so: So the overall resulting temperature coefficient of resistance became slightly different than pure platinum. I don't know about any doping involved. Allassa37 (talk) 05:48, 17 January 2021 (UTC)