Introduction to Instrumentation and Control Systems

Measurement:
It is defined as the study of physical and chemical parameters of any object by comparing with standards.
The word measurement is used to tell us the length, weight, temperature, colour or change in any physical parameters of the material.

Instrumentation:
It is a technology of using instrument to measure and control physical and chemical parameters/properties of the material.

Methods of measurement:
(a) Direct and indirect measurement.
(b) Primary secondary and tertiary measurement.
(c) Contact and non contact type measurement.


(a) direct and indirect measurement
Direct measurement: the value of physical parameters is determined by comparing it directly with different standards.
Indirect measurement: the value of physical parameters is determined by indirect comparison with secondary standard calibration.

(b) Primary secondary and tertiary measurements:
Primary measurement:
In this measurement the physical parameters is determined by Reference standards.

Secondary and tertiary measurement:
The secondary and tertiary measurement are indirect measurements involving 1 transmission are called secondary measurements. And those involving two transmissions are called tertiary measurement.
Example: temperature is measured by a mercury in a class.
Pressure is measured by boundary tube.


(c)Contact and non-contact measurements:
Contact measurement:
Sensing element of a measuring device as contact with the medium.
Example: thermometer.

Non-contact measurement:
Sensing element of a measuring device does not have physical contact with the medium.
Example: laser


Tags: ICS, measuremt, measuring,instrumentation