 Hello, I am Milka Juggle, working as assistant professor in Department of Mechanical Engineering Wolchen Institute of Technology, Solapur. Today, we are going to learn about static characteristics of instrument. Let us see, learning outcome. At the end of this session, learner will be acquainted with static terms and characteristics of measurement instrument. So, this is the content for today's presentation, instrument characteristics, what are various instrument characteristics that is static and dynamic and the static characteristics. In this video, we will be learning about static and in the next video, we will see dynamic characteristics. Instrument characteristic, instrument performance is described by means of quantitative qualities which are referred as characteristics, those are static and dynamic characteristics. So, let us see what is static characteristics. Static characteristics belong to a system where quantities to be measured are constant or may vary slowly with time. Dynamic characteristics, in this dynamic characteristics, when the instrument is required to measure a time varying process variable, if the process variable is not constant and it varies with respect to time, then that has to be concerned with dynamic characteristics, which quantify the dynamic relation between instrument input and output. So, these are the two characteristics, static and dynamic characteristics. So, now I want you to pause the video for few seconds and list down few static and dynamic characteristics you know. The measured is constant, then static and the dynamic is when it changes with respect to time. So, let us see what are static characteristics. First one, range and span. So, range is the region between the limits within which an instrument is designed to operate, to measure, to indicate or to record a physical quantity. So, if you take an instrument to measure some quantity, then the limits, it will have an upper and lower limit. So, that region, the region between upper and lower limit is known as range, range of that particular instrument. Span, span represents the algebraic difference between upper and lower range. So, let us see an example of, you will understand if we will take an example. So, range, if a voltmeter is used to measure the voltage within a range of 0 volt to 75 volts, then the range of that voltmeter will be 0 to 75, the region is nothing but the range of that voltmeter is 0 volt to 75 volt. So, in the same way, if the range of the thermometer is measuring the temperature between minus 20 to 60 degree, so here the range is minus 20 degree to 60 degree is the range, whereas span, as we have discussed, span is the algebraic difference between the upper and lower range value. Now, the thermometer upper range value is 60 and the lower range value is minus 20, 60 minus of minus 20, that is range is 80 degrees and here the range is 75 minus 0, that is 75 volts. I hope you understood the range and the span. Now, let us see accuracy error and correction, accuracy. Accuracy is nothing but degree of closeness to the true value or to the standard value as the slide shows, accuracy of an indicated value may be defined as closeness to an accepted standard value. So, it is nothing but degree of closeness to the standard value. Figure 2 shows the accuracy. In this diagram, it shows that all the arrows are striped at the bull's eye, so it is known as accurate, the shots are known to be accurate, so the difference between measured value and true value of the quantity is expressed as an instrument error. This is our area of interest, that is bull's eye, the arrows are to be targeted here and all the arrows are accurately targeted in this bull's eye region. The difference between true value and measured value of the quantity is correction. The instrument ability to reproduce a certain group of readings with accuracy is known as precision. Ability of instrument to give same readings over and over again for a constant input signal is known as precision. So, figure number 3 shows example of precision. So here, our target is bull's eye, but all the arrows are striped on the particular area. The arrows are striped on this particular region, so these readings are said to be precise readings. Calibration, can you tell me what is calibration? Calibration is nothing but comparing with the standards, comparing the measurement with the standards. So the entire procedure led down for making, adjusting or checking a scale, so that readings of an instrument or measurement system conform to an accepted standard is called as calibration. So figure number 4 shows calibration. So the instruments need to be calibrated in equal interval of time, then only the readings given by the instruments or results of the instrument are accurate. Repeatability, the name itself indicates it is nothing but ability of a system or ability of an instrument to give same output for repeated applications of same input value or same conditions of measurement. If an instrument gives the repeated readings of same value for same input, then that is known as repeatability. Now figure number 5 shows this diagram shows it is accurate and repeatable. Here it shows it is not accurate but it is repeatable. Third figure shows it is accurate but not repeatable whereas fourth shows not accurate and not repeatable. In this we need to focus on first and second diagram that is in this two the readings are repeatable. So just concentrate, do not concentrate on accuracy just see the repeated readings. Here the readings or the shots are repeatable. Reproducibility, reproducibility describes the ability to be reproduced or copied. It is closeness between measurements of same quantity when measurements are made under different conditions like different locations, different operators, different conditions of instrument and different instruments and over a long period of time. So figure number 6 shows reproducibility. So if you see here it is repeatability and it is reproducibility and this line shows the reference value. The working range of most of the instruments provide linear relationship between output and input. So we know the straight line equation is y equal to mx plus c. So linearity is also defined as ability to reproduce the input characteristics symmetrically and this can be expressed by straight line equation. So this is nothing but linearity. This is the red color line is best fit line and actual reading is this one, black one. So there is the figure number 7 shows linear relationship of sensor output versus pressure. Threshold, so what is threshold? Threshold defines the minimum value of input which is necessary to cause detectable change from zero output. Threshold can be caused by backlash or internal noise. These both figure shows the threshold. This is the threshold region that is detectable change is caused from zero input. In most of the digital system when the power is supplied it needs to show or it needs to reflect on the recorder systems or display systems. When input signal is increased from non-zero value it is observed that output does not change until certain input increment is exceeded or resolution can also be defined as smallest change of input for which there will be a change of output. So these are the references. Thank you.