 Hello, I am Milka Jagle, working as assistant professor in Department of Mechanical Engineering Wolchen Institute of Technology, Solapur. Today, we are going to learn introduction to measurement systems. Let's see, learning outcome. At the end of this session, learner will be acquainted with different measurement systems. This is the content, instrumentation, measurement system, methods of measurement system, classification of instruments. Instrumentation. The device of engineering science which deals with measuring techniques, devices and their associate problems is called instrumentation. Instrumentation is the technology of making measurements. It implies the application of instruments for sensing, measurement, control and monitoring of physical variables. So, let's see what is measurement. It is a way of describing how long, how heavy or how large or how deep an object is. The word measurement is used to tell us length, weight, temperature or change in physical entities of material. This shows fundamental measuring process. So, here the known quantity that is the standard value and the measured value are compared. To get the result or read out, the quantity to be measured and the known quantity are compared. So, this is how the measurement takes place and the result is read out. So, this is the process of measurement. So, now I want you to pause the video for few seconds and think on this question, what is need or what is the necessity of measurement? So, why we measure or why do we do measurements? Measurement is used to validate the new and improved design. It is used to validate the old design and new design and give the suggestions for new improved design. It is used in quality control and to separate the defective products. It is also used to monitor the data and its processing. Methods of measurement. So, there are three methods that is direct and indirect measurements, primary, secondary and tertiary measurement, contact and non-contact type of measurements. See one by one direct and indirect measurements. The value of physical parameter is determined by comparing it with the standard reference or in this the quantity to be measured is compared with the international standards which are proven. The physical standards like mass, length and time are measured by direct measurement. The value of physical parameter is more generally determined by indirect comparison with secondary standards through calibration. Primary secondary and tertiary measurements. Based upon the complexity of measurement systems, the measurements are generally grouped into three categories. First primary, second secondary and third is tertiary. So, primary measurements. In the primary mode, the value of physical parameter is determined by comparing it with reference standards. The required dimension is obtained to the senses of sight and touch. For example, matching of two lengths is determined, for example, matching of two lengths by determining the length of an object with a ruler. The second example is estimating the temperature difference between the components of the container by inserting fingers. Use of beam balance measure masses and measurement of time by counting a number of strokes of a block. Secondary and tertiary measurement. Secondary and tertiary measurements are the indirect measurement involving one translation are called secondary and those involving two conversion or two translations are called tertiary measurement. Example, conversion of pressure into displacement by means of bellows and the conversion of force into displacement using spring. Pressure measurement by manometer and temperature measurement by mercury in glass tube thermometer. The measurement of static pressure by boundary tube pressure gauge is a typical example of tertiary measurement. So, the next one is contact and non-contact type of measurement. So, first one is contact type. The name itself indicates when the sensing element of measuring device, when the sensing element of measuring device is in contact with medium whose characteristics are to be measured. So, these are contact type and the non-contact type, the contact between the major measurement instrument is not indirect contact. So, these are the electrical or electronic devices. So, classification of instruments. The automatic and manual instruments, self-generating and power operated instruments, self-contained and remote indicating instruments, deflection and null output instruments and analog instruments. So, automatic, the name itself indicates it is the manual instruments require the services of an operator while automatic systems does not. In manual instruments, human need to interfere for measurement whereas in automatic it does not. For example, temperature measurement by mercury in glass thermometer and temperature measurement by resistant thermometer incorporating with stone meter bridge in that manual operation, it needs operator for obtaining the null position, self-generating and power operated instrument. Self-generating instruments are the instruments in which the output is supplied entirely by the input signal, the instrument does not require any outside power in performing its function. Example, mercury in glass thermometer, burden pressure gauge, pitot tube for measuring velocity. Now, the next is self-contained and remote indicating instruments. Self-contained instruments, the different elements of self-contained instruments are contained in one physical assembly whereas remote indicating, they are located at sufficiently long distance from secondary indicating element. The next is null and deflection output instruments, null instrument. In null type instrument, the physical effect caused by the quantity being measured is nullified by generating an equivalent opposing effect. The equivalent null causing effect then provides a measure of unknown quantity. Deflection instrument, the type of instrument in which the physical effect generated by measuring quantity is noted and correlated at the to the measurement. Deflection instrument, type of instrument in which the physical effect generated by measuring quantity is noted and correlated to the measurement. So, analog and digital instruments. Analog instruments, the signals of an analog unit vary in a continuous fashion and can take on infinite number of values in a given range. Example, wrist watch, speedometer of an automobile, fuel gauge, amateurs and voltmeters are example. Digital instruments, signals varying in discrete steps and taking on a finite number of different values in a given range are digital signals. Signals varying in discrete steps and taking on finite number of different values in a given range are digital signals and corresponding instruments are of digital type. Example, timer on scoreboard, odometer of an automobile are examples of instruments. The content is referred from mechanical measurements and controlled by Dr. D. S. Kumar. Thank you.