PURPOSE OF INSTRUMENTATION:

PURPOSE OF INSTRUMENTATION:

The primary purpose of an instrument is to measure a process condition (process variable = process parameter), such as pressure, temperature, level, flow, humidity, strain, displacement or anyone of large number of possible process variables.

After measurement the information provided by the instrument can be used for the following purposes (called secondary purposes).

a)  CONTROL A PROCESS:  Controlling of process may be either manual or automatic. The Flow of a liquid may be controlled using flow meter/valve combination and the level by level gauge/valve combination.

b)  COSTING THE PROCESS: Cost of electricity (i.e. energy) consumption and cost of gas consumed can be evaluated means of house -hold electricity meter (watt –hour meter) and by gas meter. Meter at petrel pump can be used to evaluate the cost of process (cost of petrol which is filled in the tank of vehicle)

c)  TO MAINTAIN PERSONAL SAFETY:  Whole body counter film badges, dosimeter etc are used at the plant for personnel safety. Control of radioactivity, tripping of reactor for high reactivity and ∆T use of protective/ regulating systems are the examples for maintaining personnel safety as well as plant safety.

d)  SAFETY AND EFFICIENCY OF PLANT:  Different alarms and tripping of reactor in abnormal conditions may be used for maintaining safety and efficiency of plant.

e)  PROCESS REDESIGN:  The information provided by the measurement can be used for process, redesign  The defects and deficiencies can be removed. The process line piping network can be simplified removing or eliminating unwanted signals.