Important Short Questions and Answers: Basics of Measurement and Instrumentation

BASICS OF MEASUREMENT AND INSTRUMENTATION

1. What are the basic elements of a generalized measurement system?

Ø Primary sensing element which is generally a transducer. Data conditioning element which further consists of variable conversion element and variable manipulation element.

Ø Data transmission and presentation elements which include data transmission system and data display system.

2. List any four Static characteristics of a measuring system.

Accuracy, Precision, Error, Resolution, Stability, Linearity etc.

3. Define the term Accuracy.

The accuracy is defined as the degree of closeness with which the instrument reading approaches the true value of the quantity to be measured. It indicates the ability of an instrument to indicate the true value of the quantity.

4. What is an Error?

The algebraic difference between the indicated value and the true value of the quantity to be measured is called an error.

5. What is calibration?

Calibration is the process of making an adjustment or making a scale so that the readings of an instrument agree with the accepted value and the certified standard.

6. What is exact difference between accuracy and Precision?

Accuracy indicates how far the measured value is close to the true value while precision indicates how for a particular measured value is from the average of readings taken. Thus precision is not related to true value of the parameter to be measured.

7. Define the term Precision.

It is the Measure of consistency or repeatability of measurements. It denotes the amount by which the individual readings are departed about the average of number of readings.

8. Mention the basic requirements of measurement.

Ø The standard used for comparison purpose must be accurately defined and Should be commonly accepted.

Ø The apparatus used and the method adopted must be provable.

9. What is a transducer?

Ø It is device that receives energy from one system and transmits it to another, often in a different form.

10.            Explain the function of measurement system.

The measurement system consists of a transducing element which converts the quantity to be measured in an analogous form. The analogous signal is then processed by some intermediate means and is then fed to the end device which presents the results of the measurement.

11.            Give the applications of measurement systems.

Ø The instruments and measurement systems are sued for

Ø Monitoring of processes and operations.

Ø Control of processes and operations.

Ø Experimental engineering analysis.

12.            Define static characteristics.

Static characteristics are the set of rules or criteria that is defined for those instruments that varies very slowly with time or remains a constant.

13. Define Dynamic characteristics.

Dynamic characteristics are the set of rules or criteria that is defined for those instruments that varies very rapidly with time.

14.            What are the various Dynamic characteristics?

Ø Various Dynamic characteristics are

Ø Fidelity

Ø Speed of Response

Ø Time Delay

Ø Lag

Ø Dynamic error

15.            State the advantages of Maxwell-wein bridge.

The balance equation is independent of frequency and therefore more accurate.

16. State the disadvantage of Maxwell-wein bridge.

This method needs a standard variable capacitor. Variable Capacitor is costliest.