iTHERM TM412
4
Hauser
There are generally two different kinds of platinum resistance thermometers:
• Wire wound (WW): Here, a double coil of fine, high-purity platinum wire is located in a ceramic
support. This is then sealed top and bottom with a ceramic protective layer. Such resistance
thermometers not only facilitate very reproducible measurements but also offer good long-term
stability of the resistance/temperature characteristic within temperature ranges up to
600 °C (1
112 °F). This type of sensor is relatively large in size and it is comparatively sensitive to
vibrations.
•
Thin film platinum resistance thermometers (TF):
A very thin, ultrapure platinum layer,
approx. 1 μm thick, is vaporized in a vacuum on a ceramic substrate and then structured
photolithographically. The platinum conductor paths formed in this way create the measuring
resistance. Additional covering and passivation layers are applied and reliably protect the thin
platinum layer from contamination and oxidation, even at high temperatures.
The primary advantages of thin film temperature sensors over wire wound versions are their smaller
sizes and better vibration resistance. A relatively low principle-based deviation of the resistance/
temperature characteristic from the standard characteristic of IEC 60751 can frequently be observed
among TF sensors at high temperatures. As a result, the tight limit values of tolerance category A as
per IEC 60751 can only be observed with TF sensors at temperatures up to approx. 300 °C (572 °F).
Measuring system
Hauser offers a complete portfolio of optimized components for the temperature measuring
point – everything you need for the seamless integration of the measuring point into the overall
facility. This includes:
• Power supply unit/barrier
• Display units
• Data managers
• Overvoltage protection
For more information, see the brochure 'System Products and Data Managers - Solutions for the
loop' (FA00016K)
FieldCare
Memograph M
RSG45
RIA15
TM4xx
PLC
A0033768
1
Example of application, measuring point layout with additional Hauser components
Summary of Contents for iTHERM TM401
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