Temperature measurement

Basic principles of temperature measurement

Temperature is the most frequently measured parameter in the process industry.

In electrical, contact thermometers two measurement principles have asserted themselves as a standard:

RTD: resistance sensors

In RTD resistance sensors the electrical resistance changes with a change in temperature. They are suitable for the measurement of temperatures between -200°C and +800°C and stand out due to high measurement accuracy and long-term stability. The resistance sensor element most frequently used is a Pt100 that has a nominal value of 100Ω at 0°C. Pt100 sensors are manufactured in different formats:

	Wire wound ceramic sensors: a spiral of platinum wire is wound and embedded in ceramic powder within a capillary and is fed to the outside by platinum wires.
	Thin film sensors: a platinum layer is vaporized on a ceramic plate (sputtered). A glass layer is melted on in order to protect the connection wires and the platinum layer.

TC: thermocouples

A thermocouple is a component made of two different metals connected with each other at one end. An electrical potential (thermoelectric force) is caused due to the Seebeck effect at the open end if the connection and the free ends are exposed to different temperatures. With the help of the thermocouple reference tables (see IEC 584), the temperature at the connection (measuring junction) can be calculated.

Thermocouples are suitable for temperature measurement from 0°C to +1800°C.

Segmentation

"You only pay for what you really need."  We take this statement seriously at Endress+Hauser and offer our instruments in three different segments.

S-M-T segment

The classification in these 3 segments allows you to select an instrument tailormade to your requirements. Our products always stand for high quality and reliability regardless of the segment you choose. 

Omnigrad S: The S-class for best performance in rough conditions

Omnigrad M: The M-class with industry specific design

Omnigrad T: The economic T-class