2. Public
Semih Dogan
Kocaeli University
06.11.2014
Introduction to Temp.
Sensors
3. Public, Temperature Sensors, 3 Introduction to Temp. Sensors
Semih Dogan, Kocaeli University, 06.11.2014
What is Temp. Sensors?
– Temperature Sensors are devices that can sense the difference amount of heat
between application space and reference.
– They are used to measure temperature and change of heat transfer of a medium.
4. Public, Temperature Sensors, 4 Introduction to Temp. Sensors
Semih Dogan, Kocaeli University, 06.11.2014
Type of temperature measuring devices
– Thermometers
– Thermocouples
– Resistance Temperature Detectors (RTD’s)
5. Public, Temperature Sensors, 5 Introduction to Temp. Sensors
Semih Dogan, Kocaeli University, 06.11.2014
Thermometers
– Filled Thermometers are filled with a liquid such as heat can cause expansion or
evoporation on it. So that, liquid can pressurized. The pressure is related to the
temperature and it may be indicated on a simple gauge.
– Advantage: low cost, simple
– Disadvantage: no remote measurement
6. Public, Temperature Sensors, 6 Introduction to Temp. Sensors
Semih Dogan, Kocaeli University, 06.11.2014
Thermometers
– Bimetal thermometers are constructed by bonding two metals with different
coefficients of thermal expansion.
– If heat is applied to the end of strip, the metal with the higher coefficient of expansion
will bend more than lower one.
7. Public, Temperature Sensors, 7 Introduction to Temp. Sensors
Semih Dogan, Kocaeli University, 06.11.2014
Thermocouples
– A thermocouple consist of two pieces of dissimilar metals with their ends joined
together. (twisting, soldering, welding)
– When the heat is applied to the junction, a voltage (emf) in the range of mV is
generated.
– The voltage of emf produced depends on;
– 1. Types of material used
– 2. Temperature of junction, measuring and referance.
8. Public, Temperature Sensors, 8 Introduction to Temp. Sensors
Semih Dogan, Kocaeli University, 06.11.2014
Thermocouples
A construction of a J type Thermocouple
9. Public, Temperature Sensors, 9 Introduction to Temp. Sensors
Semih Dogan, Kocaeli University, 06.11.2014
Thermocouples
– The table belows shows the different types of thermocouples with construction of
non-similar metals.
10. Public, Temperature Sensors, 10 Introduction to Temp. Sensors
Semih Dogan, Kocaeli University, 06.11.2014
Thermocouples
– This chart shows the characteristics different types of thermocouples.
11. Public, Temperature Sensors, 11 Introduction to Temp. Sensors
Semih Dogan, Kocaeli University, 06.11.2014
Resistance temperature detectors ( RTD )
– RTD’s are the resistance of a conductor usually increase as the temperature
increase.
– If the properties of that conductor are known, the temperature can be calculated from
the measured resistance.
– The most common RTD’s are PT100, PT 1000 and Ni100
– The different RTD’s analyse 0°C with different resistive values. For example, PT 100
is 100Ω at 0°C.
– The temperature can be found by using The Callender Van-Dusen equations.
12. Public, Temperature Sensors, 12 Introduction to Temp. Sensors
Semih Dogan, Kocaeli University, 06.11.2014
Resistance temperature detectors ( RTD )
– RTD’s has different wiring and connection type for sensitivity of application.
– Lead and reference pins are depending on measurement sensitivity.
13. Public, Temperature Sensors, 13 Introduction to Temp. Sensors
Semih Dogan, Kocaeli University, 06.11.2014
Resistance temperature detectors ( RTD )
– Stability in the temperature range to measured. The material must be not
melt,correde,embattle or change electrical characteristics when subjected to the
environment in which it will operate.
– Linearitiy the resistance change with temperature should be as linear as possible
over the range of interest to simplfy readout.
– Response Time If the process requires a very fast response to temperature changes,
RTD’s are the best choice. Time response is measured around e.g. 2.5ms to 10ms
– Workability the material must be suitable for configurating for insertation into media.
– Range most RTD’s can operate -200 to 600°C
14. Public
Semih Dogan
Kocaeli University
06.11.2014
Experiment with PT100
(RTD) Controlled Heat and
Cool Operation of A
Medium
15. Public, Temperature Sensors, 15 Introduction to Temp. Sensors
Semih Dogan, Kocaeli University, 06.11.2014
Experiment
– By the reference of RTD, we can control the temperature of a medium in a specified
range.
– PT 100 is connected to the Endress-Hauser which is a universal indicator by the
output of this process indicator, cooling for Fan or heating cartridge heaters will be
activated.
– Relay outputs of RTD analyser can control 2 contactors of heat and cool operation.
– Delay time, set point, hysteresis, output functions, display operations can be
programmed by EEPROM inside of indicator.
16. Public, Temperature Sensors, 16 Introduction to Temp. Sensors
Semih Dogan, Kocaeli University, 06.11.2014
RTD Controlled Heat&Cool of Medium
17. Public, Temperature Sensors, 17 Introduction to Temp. Sensors
Semih Dogan, Kocaeli University, 06.11.2014
Construction of Block and Electrical Panel
18. Public, Temperature Sensors, 18 Introduction to Temp. Sensors
Semih Dogan, Kocaeli University, 06.11.2014
Electrical Connections of Panel
19. Public, Temperature Sensors, 19 Introduction to Temp. Sensors
Semih Dogan, Kocaeli University, 06.11.2014
RTD Controlled Heat&Cool of Medium
– Endress Hauser RIA 250
20. Public, Temperature Sensors, 20 Introduction to Temp. Sensors
Semih Dogan, Kocaeli University, 06.11.2014
RTD Controlled Heat&Cool of Medium
21. Public, Temperature Sensors, 21 Introduction to Temp. Sensors
Semih Dogan, Kocaeli University, 06.11.2014
RTD Controlled Heat&Cool of Medium
22. Public, Temperature Sensors, 22 Introduction to Temp. Sensors
Semih Dogan, Kocaeli University, 06.11.2014
RTD Controlled Heat&Cool of Medium
23. Public, Temperature Sensors, 23 Introduction to Temp. Sensors
Semih Dogan, Kocaeli University, 06.11.2014
Conclusion
– In general, thermocouples are cheaper, more durable and can measure a bigger
range of temperature while RTD’s produce better and more reliable measurements.
– Both temp. Sensors are versatile that have high accuracy over a wide range of
industrial applications.
24. Semih Dogan, Kocaeli University, 06.11.2014
Thank you very much
Public, Temperature Sensors, 24 Introduction to Temp. Sensors