Notes

Pt100, Pt1000 or NTC ? which is the proper sensor?
Especially the machine-building industry often asks me which is the proper measuring element for them. This is the reason why I would like to explain in this article the differences between your mostly used sensors Pt100, Pt1000 and NTC. I'll go into more detail about the lesser-used measuring elements Ni1000 and KTY sensors in the comparison by the end of this article.
Application regions of Pt100, Pt1000 and NTC
Resistance thermometers based on Pt100, Pt1000 (positive temperature coefficient PTC) and NTC (negative temperature coefficient) are employed everywhere in the industrial temperature measurement where low to medium temperatures are measured. Along the way industry, Pt100 and Pt1000 sensors are employed almost exclusively. In machine building, however, often an NTC can be used ? not least for cost reasons. Since meanwhile the Pt100 and Pt1000 sensors are manufactured in thin-film technology, the platinum content could be reduced to the very least. As a result, the purchase price difference compared to the NTC could possibly be reduced to this extent a changeover from NTC to Pt100 or Pt1000 becomes interesting for medium quantities. Particularly since platinum measuring resistors offer significant advantages over negative temperature coefficients.
Advantages and disadvantages of the different sensors
The platinum elements Pt100 and Pt1000 provide advantage of meeting international standards (IEC 751 / DIN EN 60 751). Due to material- and production-specific criteria, a standardisation of semiconductor elements such as for example NTC is not possible. For this reason their interchange ability is bound. Further benefits of platinum elements are: better long-term stability and better behaviour over temperature cycles, a wider temperature range in addition to a high measurement accuracy and linearity. High measurement accuracy and linearity are also possible having an NTC, but only in an exceedingly limited temperature range. While Pt100 and Pt1000 sensors in thin-film technology are ideal for temperatures up to 500�C, the typical NTC can be utilized for temperatures around approx. 150�C.
Influence of the supply line on the measured value
The lead resistance affects the measurement value of 2-wire temperature sensors and should be considered. For copper cable with a cross-section of 0.22 mm2, the following guide value applies: 0.162 ?/m ? 0.42 �C/m for Pt100. Alternatively, a version with Pt1000 sensor could be chosen, with that your influence of the supply line (at 0.04 �C/m) is smaller by way of a factor of 10. The influence of the lead resistance when compared to base resistance R25 for an NTC measuring element is far less noticeable. As a result of sloping characteristic curve of the NTC, the influence at higher temperatures increases disproportionately in case of higher temperatures.
Conclusion
In the event of high quantities, using NTC sensors continues to be justified because of cost reasons. For small to medim-sized lots, I would recommend the use of a platinum measuring resistor. The usage of a Pt1000 manufactured in thin-film technology is really a perfect compromise between your costs on the main one hand and the measurement accuracy on the other. In the following table, I've compiled the strengths and weaknesses of the various measuring elements within an overview for you:
Strengths and weaknesses of different sensors
NTC
Pt100
PT1000
Ni1000
KTY
Temperature range
?
++
++
+
?
Accuracy
?
++
++
+
?
Linearity
?
++
++
+
++
Long-term stability
+
++
++
++
+
International standards
?
++
++
+
?
Temperature sensitivity (dR/dT)
++
?
+
+
+
Influence of the supply line
++
?
+
+
+
Characteristic curves of Pt100, Pt1000, NTC, KTY and Ni1000
The characteristic curves of the various measuring elements can be seen in the following overview:
Characteristic curves of the different sensors
Note
Our temperature sensors for the machine-building industry can be found with all common measuring elements. pressure gauge วัด แรง ดัน น้ำ can be found on the WIKA website.
Discover more about the functionality of resistance thermometers with Pt100 and Pt1000 sensors in the following video:
Read More: http://www.stes.tyc.edu.tw/xoops/modules/profile/userinfo.php?uid=451104