Download presentation
Presentation is loading. Please wait.
Published byKristopher Greene Modified over 9 years ago
1
Mechanical Measurement and Instrumentation MECN 4600
Professor: Dr. Omar E. Meza Castillo Department of Mechanical Engineering Inter American University of Puerto Rico Bayamon Campus
2
Tentative Lecture Schedule
Topic Lecture Basic Principles of Measurements Response of Measuring Systems, System Dynamics Error & Uncertainty Analysis 1, 2 and 3 Sensor & Transducers Basic Electronics, Signal Processing 4 Measurement of Pressure 5 Measurement of Temperature 6 Measurement of Fluid Flow 7 Measurement of Level 8 Measurement of Stress-Strain 9 Measurement of Time Constant 10
3
Topic 7: Measurement of Temperature
RTD & Thermistor
4
To measure temperature using a RTD & Thermistor.
Course Objectives To measure temperature using a RTD & Thermistor.
5
RTD Types of RTD
6
RTD RESISTANCE TEMPERATURE DETECTORS (RTDs).-
RTD’s functions as a result of increasing resistance in proportion to increasing temperature. i.e, with a known current, as temperature increases, voltage increases. As a known current is placed through the RTD, the output voltage indicates RTD resistance. Since the relationship between the resistance and temperature is known, the temperature can thus be determined. The resistivity of the metal used in a RTD is dependent upon the temperature. Platinum has the best range and is the most common metal used.
7
Glass Wire Wound Platinum RTD Elements - Class B
Suitable for Low or very High Temperatures Tolerant of Thermal Shocks Good Vibration Resistance Alpha =
8
RTD (PT100) Probes Temperature Range -200 to 600°C Alpha = Standard Ro = 0°C
9
RTD The general equation is:
La ecuación general puede ser simplificada para materiales comunes como platino, cobre, etc con bajos porcentajes de error en las mediciones.
10
RTD Where: R= Resistance at temperature T
Ro= Resistance at temperature To To= Temperature of reference T= Temperature α= Resistivity Coefficient
11
Theory Experiment Circuit for the laboratory Where:
eo= Voltage through RTD Rb= Resistance RRTD= Resistance RTD ei= Voltage of fem D M ei (fem) + I Rb RRTD eo
12
Analysis Kirchoff’s Law: Law of Ohm
13
Analysis Combining previous Equations:
14
Laboratory: Find the value of α
Table of Data Setup the circuit with a ei=10V Measure the Ro at T=0ºC Obtain the value of Rb Increase temperature and measure eo In order to find α, use the following equation Obtain the value of α using least squared method Compare α with values of literature. T(ºC) eo(V) ()
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.