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 advantages are good accuracy, almost linear characteristics, and stability. The temperature of the bar is constant at 62f and, 2. The dewpoint temperature is usually equal to or lower than the actual air temperature. So, first we will start our discussion with classification of. A disadvantage is the small change of resistance with temperature, which requires a high sensitivity from the rest of the measurement equipment. Apr 19, 2016 various types of thermometers, measuring temperature, how they are used, learning for children duration. Explain the surface temperature measurement using a compensated probe 65. If you unplug a signal and dont get an alarm its not designed fail safe.
The most important methods for measuring temperature and their basic principles are described. T is the temperature in kelvin r is the resistance at t and r ref is resistance at t. Cooling of sea foods, meat sea export, milk products for long time preservation is achieved by use of ln2. Trainin wwnttiom introduction to instrumentation and process control. 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. Differentiate characteristics of a ptc thermistor from a ntc thermistor.
The first edition of this book was copublished by ane books india, and crc press in 2008. Principles and methods of temperature measurement course content temperature can be measured via a diverse array of sensors. However, the science of temperature measurement has. In our previous lecture we have talked about rtd which is based on changes in. Explain the electrical analogy of temperature sensor as a first order system. Celsius to fahrenheit converter with formula and solved example. Resistance thermometer an overview sciencedirect topics. Ntt recommends a class of 12 participants to obtain the best results. Helect infrared thermometer noncontact digital laser infrared temperature gun. Another common temperature sensor is the silicon diode. The present volume covers two broad subjects of very wide interesttemperature and chemical compositionboth of which are important for process control.
They are ideal where vapor, dust, or a foaming surface prevents ultrasonic measurement. 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. Celsius and fahrenheit are the measures of temperature. Nptel video lectures, iit video lectures online, nptel youtube lectures, free video lectures, nptel online courses, youtube iit videos nptel courses. It is a type of temperature sensor, which is made by joining two dissimilar metals at one end. In close cooperation with our customers and users, our application engineers create concepts to meet the measurement requirements.
Temperature is a measure that basically tells us the degree of hotness or coldness of any object. Temperature measurement nptel free download as pdf file. Bimetallic temperature measurement devices bimetallic devices take advantage of the difference in rate of thermal expansion between different metals. Radar level transmitters in applications requiring noncontact measurement of liquid levels, the affordable lvrd500 radar transmitter is the logical extension of ultrasonic sensors. Tmp117 functional block diagram ti temperature sensors and design tips to learn more about some of ti temperature sensors, refer to table 1. Measurement and control of temperature is an important component of cryogenic systems. Mechanical measurements and metrology nptel online videos. Lecture measurement of temperature under various conditio.
The air stream attains thermal equilibrium with water at temperature tas and also gets saturated with water vapor at that temperature before it leaves. Principle of measurement of temperature by a thermocouple. The device that is used to measure temperature is mostly called as thermometer, which is believed to be invented by galileo. Basic rtd measurements basics of resistance temperature detectors. At the same time, it forms an important basis for continued innovation. So this will be lecture number 14 on our ongoing series on mechanical. Temperature measurements and sensor characteristics objectives. Various types of thermometers, measuring temperature, how they are used, learning for children duration. The purpose of early thermometers was to measure the variation of atmosphere or body temperature. 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. Thus, atmospheric temperature is one of the most important meteorological elements as well as wind and. There are a wide variety of temperature sensors on the market today, including thermocouples, resistance temperature detectors rtds, thermistors, infrared, and semiconductor sensors. So, we are into the second lecture of our week number 10 where we.
Use of thermocouples for measurement of temperatures particularly in higher range of temperatures. Because scientists around the world must agree on the definition and interpretation of temperature there is a political element to those agreements. Temperature international standard of measurement 20. The space above the mercury may be filled with nitrogen or it may be. The emf driving the current is called a thermoelectric emf and the phenomenon. Me343 lecture note 5 temperature measurements and sensor. The photoelectric transducer converts the light energy into electrical energy. Celsius to fahrenheit converter with formula and solved. Humidity measurement is an important tool for predicting the climate outdoors as well as controlling the climate indoors.
Lecturemeasurement of temperature under various conditio. Properties of materials vary considerably with temperature thermal properties. The photoelectric transducer uses a photosensitive element, which ejects the electrons when the beam of light absorbs through it. Temperature gun noncontact infrared ir thermometer range 58f to 1022f w fluke 51ii thermometer. It is a serious job to select the proper materials for a thermocouple. May 18, 2008 lecture series on industrial automation and control by prof. Dewpoint temperature is the air temperature at which the moist air saturates respect to water at a given pressure.
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. Welcome to lecture 39 we are talking about temperature measuring instruments. Ordering information 9100s handheld drywell 9300 rugged carrying case, 9100. The key optimized parameters as well as their tradeoffs are listed. Easily connect a fluke 754 to a drywell for a fully automated temperature calibration that includes the temperature transmitter and temperature sensor. Errors in measurement controllable errors environmental conditions. The unique cryogenic features have to do with instrumentation used to detect signal and need for low heat leak. The matter presented here is prepared by the author for their respective teaching assignments by referring the text books and reference books. Numerous practical details provide the user with valuable information about temperature measurement in industrial applications. This is the main application, but we will touch some of the.
If sufficient time is allowed, a steady state temperature will be attained by drop. All of them infer temperature by sensing some change in a physical characteristic. 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. 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. He has developed a web based course and a video lecture series on mechanical measurements under the nptel project of iit madras. The results of inspection are not only recorded but forwarded to the manufacturing department for taking.
Classification, absolute and secondary instruments, indicating instruments, control, balancing and damping, constructional details, characteristics, errors in measurement, ammeters, voltmeters. Select the proper thermocouple for a particular temperature range. 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. Measurement of temperature and chemical composition is the second in a fourvolume series of instrument technology. It states that when two bodies are in thermal equilibrium, they are. 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.
Since almost all pressure sensors measure a pressure difference, we need to distinguish between absolute and gauge pressures. The ptc thermistor is not common for temperature measurement but is very common when used as a selfresettable fuse. Types of temperature sensors and their working principles. Temperature driving force for heat transfer from ambient air to water increases. This temperature distribution generates wind current along with cloud and rainfall phenomena. Commercial platinum wire has a standard temperature coefficient, called alpha, of 0. Even though it is a thermocouple circuit, but that semiconductor temperature sensor will be utilized to make the cold junction compensation. Although these sensors have overlapping temperature ranges, each has certain applicationdependent advantages. Dimensional measurements at the required level of accuracy are the essential link between the designers intent and a delivered product.
Provide the means of finding out shortcomings in manufacture. Humidity control is especially important in living, storage, and manufacturing sites. 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. As temperature of water drop decreases with time, vapor pressure decreases causing a reduction in partial pressure driving force. The participant is able to learnbydoing in the course. Sarkar department of chemical engineering,iit kharagpur. 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. Void fraction measurement a va a capacitance measurement b optical characterization 2. The first volume grouped the measurements of mechanical quantities. Heat capacity internal energy, thermal expansion transport properties. Preserving food at low temperature is a well known technique. To meet this wide array of needs the process controls industry has developed a large number of sensors and devices to handle this demand. 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. 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.
Basic rtd measurements basics of resistance temperature. Mechanical measurements and metrology nptel online. Piston engines lubrication b the temperature of the oil is more difficult to control as it is stored within the hot engine casing. The temperature at which moist air saturates with respect to ice is called the frost point temperature. To learn more about pcb guidelines, ambient air measurement, or linearization, refer to table 2. There are four basic types of temperature measuring devices, each of which uses a different principle. Industrial temperature measurement basics and practice. Temperature measurement nptel thermometer thermocouple. It has a very linear temperature coefficient over the normal operating range a semiconductor is used in, typically 0 to 50 c. Nptel mechanical engineering forming joint initiative of iits and iisc funded by mhrd page 5 of 10 temperature. Apr 07, 2015 he has been teaching a course in measurements in thermal engineering for over 30 years to b. The bar is supported on rollers in a specified manner to prevent flexure.
1284 652 684 842 1014 31 743 362 227 1480 570 1420 561 1444 475 1241 501 679 1449 904 597 183 599 936 1329 47 1189 535 470 267 913 465 1264