Types of temperature sensors and their working principles. Heat capacity internal energy, thermal expansion transport properties. Quality measurement m vm these techniques are for the most part all used in classical fluid flows. The bar is supported on rollers in a specified manner to prevent flexure.
Principles and methods of temperature measurement course content temperature can be measured via a diverse array of sensors. Lecture series on industrial automation and control by prof. The steinharthart equation relates temperature to resistance. Resistance temperature device rtd very accurate and stable reasonably wide temperature range more expensive platinum positive temperature constant, and rather constant requires current excitation smaller resistance range selfheating is a concern lead resistance is a concern read an 687 for more details e. Explain the electrical analogy of temperature sensor as a first order system. Dimensional measurements at the required level of accuracy are the essential link between the designers intent and a delivered product. Easily connect a fluke 754 to a drywell for a fully automated temperature calibration that includes the temperature transmitter and temperature sensor. Pressure measurement pressure is a force per unit area exerted by a fluid perpendicular to a boundary as opposed to shear stress, which is exerted parallel to the boundary.
Temperature measurement by tc sensor characteristics o sensitivity o signal drifting o response time other methods for temperature measurement o rtd o thermistor o infrared thermometer lab report requirement of lab 2 see lecture note 3 for geeral format requirement. This is the main application, but we will touch some of the. Temperature measurement nptel thermometer thermocouple. Tmp117 functional block diagram ti temperature sensors and design tips to learn more about some of ti temperature sensors, refer to table 1. Commercial platinum wire has a standard temperature coefficient, called alpha, of 0.
A small quantity of water at the temperature tas is fed to the humidification chamber continuously in order to compensate for the vaporization loss of water. To learn more about pcb guidelines, ambient air measurement, or linearization, refer to table 2. Mukhopadhyay, department of electrical engineering, iit kharagpur. It is a type of temperature sensor, which is made by joining two dissimilar metals at one end. So, first we will start our discussion with classification of. Numerous practical details provide the user with valuable information about temperature measurement in industrial applications. It is a serious job to select the proper materials for a thermocouple. Preserving food at low temperature is a well known technique. Temperature measurement is a vital part of most industrial operations and is typically accomplished by a temperature sensora thermocouple or a resistance temperature detector rtdin contact with a solid surface or immersed in a fluid. Humidity measurement is an important tool for predicting the climate outdoors as well as controlling the climate indoors. The device that is used to measure temperature is mostly called as thermometer, which is believed to be invented by galileo.
Temperature measurement nptel free download as pdf file. An australian tribe, still primitive, uses dogs instead of blankets to keep warm, thus, they can relate temperature by the dog. Mechanical measurements and metrology nptel online. A brief history of temperature measurement ancient people were physically aware of hot and cold and probably related temperature by the size of the fire needed, and how close to sit, to keep warm. Temperature is a measure that basically tells us the degree of hotness or coldness of any object. The purpose of early thermometers was to measure the variation of atmosphere or body temperature.
T is the temperature in kelvin r is the resistance at t and r ref is resistance at t. The participant is able to learnbydoing in the course. The measurement of temperature is based on zeroth law of thermodynamics. Use of thermocouples for measurement of temperatures particularly in higher range of temperatures. Errors in measurement controllable errors environmental conditions. Helect infrared thermometer noncontact digital laser infrared temperature gun. If sufficient time is allowed, a steady state temperature will be attained by drop. Apr 07, 2015 he has been teaching a course in measurements in thermal engineering for over 30 years to b. This temperature distribution generates wind current along with cloud and rainfall phenomena. Accurate temperature measurements are required in many other measurement systems such as process control and instrumentation applications. Systems are developed to preserve blood cells, plasma cells, human organs and animal organs at. The results of inspection are not only recorded but forwarded to the manufacturing department for taking.
Principle of measurement of temperature by a thermocouple. Basic rtd measurements basics of resistance temperature. Void fraction measurement a va a capacitance measurement b optical characterization 2. They are ideal where vapor, dust, or a foaming surface prevents ultrasonic measurement. May 18, 2008 lecture series on industrial automation and control by prof. If you unplug a signal and dont get an alarm its not designed fail safe. The emf driving the current is called a thermoelectric emf and the phenomenon. Liquid in glass thermometer the volume of mercury changes slightly with temperature. Provide the means of finding out shortcomings in manufacture. Even though it is a thermocouple circuit, but that semiconductor temperature sensor will be utilized to make the cold junction compensation.
This second edition is an enlarged version of the web course developed by the author at iit madras, and also a modified and augmented version of the earlier book. The temperature of the bar is constant at 62f and, 2. Their radar sensor uses microwave pulse technology to track target liquids from the antenna tip to the bottom of. The first edition of this book was copublished by ane books india, and crc press in 2008. Me343 lecture note 5 temperature measurements and sensor. The first volume grouped the measurements of mechanical quantities. The present volume covers two broad subjects of very wide interesttemperature and chemical compositionboth of which are important for process control. Cooling of sea foods, meat sea export, milk products for long time preservation is achieved by use of ln2. It states that when two bodies are in thermal equilibrium, they are. Temperature measurement by tc sensor characteristics o sensitivity o signal drifting o response time other methods for temperature measurement o rtd o thermistor o infrared thermometer lab report requirement of lab 2. The photoelectric transducer uses a photosensitive element, which ejects the electrons when the beam of light absorbs through it. The most important methods for measuring temperature and their basic principles are described.
Because scientists around the world must agree on the definition and interpretation of temperature there is a political element to those agreements. There are four basic types of temperature measuring devices, each of which uses a different principle. Although these sensors have overlapping temperature ranges, each has certain applicationdependent advantages. Temperature gun noncontact infrared ir thermometer range 58f to 1022f w fluke 51ii thermometer. Nptel video lectures, iit video lectures online, nptel youtube lectures, free video lectures, nptel online courses, youtube iit videos nptel courses.
Ntt recommends a class of 12 participants to obtain the best results. Another common temperature sensor is the silicon diode. Humidity control is especially important in living, storage, and manufacturing sites. Measurement and control of temperature is an important component of cryogenic systems. Trainin wwnttiom introduction to instrumentation and process control. It has a very linear temperature coefficient over the normal operating range a semiconductor is used in, typically 0 to 50 c. Lecturemeasurement of temperature under various conditio.
The matter presented here is prepared by the author for their respective teaching assignments by referring the text books and reference books. Welding produces a mechanical and electrical connection that creates a solid sensor starting point of zero electrical potential difference and zero temperature difference between the. The air stream attains thermal equilibrium with water at temperature tas and also gets saturated with water vapor at that temperature before it leaves. Basic rtd measurements basics of resistance temperature detectors platinum rtd resistances range from about 10 o for a birdcage configuration to 10k o for a film type, but the most common is 100 o at 0c. Celsius and fahrenheit are the measures of temperature. Celsius to fahrenheit converter with formula and solved. Explain the surface temperature measurement using a compensated probe 65. Apr 19, 2016 various types of thermometers, measuring temperature, how they are used, learning for children duration. Humidity measurement principle s bharadwaj reddy may 16, 2016 october 21, 2017 humidity measurement is an important tool for predicting the climate outdoors as well as controlling the climate indoors. So this will be lecture number 14 on our ongoing series on mechanical. The temperature at which moist air saturates with respect to ice is called the frost point temperature. The advantages are good accuracy, almost linear characteristics, and stability. The key optimized parameters as well as their tradeoffs are listed.
Select the proper thermocouple for a particular temperature range. Temperature driving force for heat transfer from ambient air to water increases. Differentiate characteristics of a ptc thermistor from a ntc thermistor. There are a wide variety of temperature sensors on the market today, including thermocouples, resistance temperature detectors rtds, thermistors, infrared, and semiconductor sensors. He has developed a web based course and a video lecture series on mechanical measurements under the nptel project of iit madras. All of them infer temperature by sensing some change in a physical characteristic. Properties of materials vary considerably with temperature thermal properties. The photoelectric transducer converts the light energy into electrical energy.
The ptc thermistor is not common for temperature measurement but is very common when used as a selfresettable fuse. Sarkar department of chemical engineering,iit kharagpur. The dewpoint temperature is usually equal to or lower than the actual air temperature. Measurement of temperature and chemical composition is the second in a fourvolume series of instrument technology.
Piston engines lubrication b the temperature of the oil is more difficult to control as it is stored within the hot engine casing. To meet this wide array of needs the process controls industry has developed a large number of sensors and devices to handle this demand. Noncontact ultrasonic level sensors with power and programming options, rs232 or rs485 communications capability, pushbutton calibration, and temperature compensated signaling, the lvu40 series ultrasonic level sensor bring another dimension of flexibility to continuous noncontact liquid level measurement. The space above the mercury may be filled with nitrogen or it may be. So, we are into the second lecture of our week number 10 where we. Various types of thermometers, measuring temperature, how they are used, learning for children duration. Temperature international standard of measurement 20.
Welcome to lecture 39 we are talking about temperature measuring instruments. When heated, one side will expand more than the other, and the resulting bending is translated into a temperature reading by mechanical linkage to a pointer. A disadvantage is the small change of resistance with temperature, which requires a high sensitivity from the rest of the measurement equipment. Methods to calibrate temperature monitoring systems. Classification, absolute and secondary instruments, indicating instruments, control, balancing and damping, constructional details, characteristics, errors in measurement, ammeters, voltmeters. Lecture measurement of temperature under various conditio.
Nptel mechanical engineering forming joint initiative of iits and iisc funded by mhrd page 5 of 10 temperature. Resistance thermometer an overview sciencedirect topics. In our previous lecture we have talked about rtd which is based on changes in. Dewpoint temperature is the air temperature at which the moist air saturates respect to water at a given pressure. Thus, atmospheric temperature is one of the most important meteorological elements as well as wind and. Ordering information 9100s handheld drywell 9300 rugged carrying case, 9100.
Metrology metrology is the science of measurement dimensional metrology is that branch of metrology which deals with measurement of dimensions of a part or workpiece lengths, angles, etc. Mechanical measurements and metrology nptel online videos. Celsius to fahrenheit converter with formula and solved example. Basic rtd measurements basics of resistance temperature detectors. At the same time, it forms an important basis for continued innovation. Bimetallic temperature measurement devices bimetallic devices take advantage of the difference in rate of thermal expansion between different metals.
However, the science of temperature measurement has. The unique cryogenic features have to do with instrumentation used to detect signal and need for low heat leak. In close cooperation with our customers and users, our application engineers create concepts to meet the measurement requirements. Temperature measurements and sensor characteristics objectives.
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