Sunday 24 May 2015

Electronics Instrumentation & Measurement

According to the Oxford English Dictionary  (as its last definition of Instrumentation), "The design, construction, and provision of instruments for measurement, control, etc; the state of being equipped with or controlled by such instruments collectively." It notes that this use of the word originated in the U.S.A. in the early 20th century.
High Level Instrumentation

Instrumentation is the use of measuring instruments to monitor and control a process. It is the art and science of measurement and control of process variables within a production, laboratory, or manufacturing area.
An instrument is a device that measures a physical quantity such as flow, temperature, level, distance, angle, or pressure. Instruments may be as simple as direct reading thermometers or may be complex multi-variable process analyzers. Instruments are often part of a control system in refineries, factories, and vehicles For example, a smoke detector is a common instrument found in most western homes.
Measurement instruments have three traditional classes of use:

1.Monitoring of processes and operations
2.Control of processes and operations
3.Experimental engineering analysis.

Measurement:- The first proposal to tie an SI base unit to an experimental standard independent of fiat was by Charles Sanders Peirce (1839–1914), who proposed to define the metre in terms of the wavelength of a spectral line.
 Any measurement of an object can be judged by the following meta-measurement criteria values: level of measurement (which includes magnitude), dimensions (units), and uncertainty. They enable comparisons to be done between different measurements and reduce confusion.Even in cases of clear qualitative similarity or difference, increased precision through quantitative measurement is often preferred in order to aid in replication.
The seven base units in the SI system. Arrows point from units to those that depend on them; as the accuracy of the former increases, so will the accuracy of the latter
Measurements are most commonly made in the SI system, which contains seven fundamental units: kilogram, metre, candela, second, ampere, kelvin, and mole. Six of these units are artifact-free (defined without reference to a particular physical object which serves as a standard); the definition of one remaining unit, the kilogram is still embodied in an artifact which rests at the BIPM(International Bureau of Weights and Measures) outside Paris. Eventually, it is hoped that new SI definitions will be uniformly artifact-free.
Artifact-free definitions fix measurements at an exact value related to a physical constant or other invariable phenomenon in nature, in contrast to standard artifacts which can be damaged or otherwise change slowly over time.

The original SI units for the six basic physical quantities were
Base quantity
Base unit
Current SI constants
New SI constants (proposed)[6]
hyperfine splitting in Cesium-133
same as current SI
speed of light in vacuum, c
same as current SI
mass of International Prototype Kilogram (IPK)
Planck's constanth
electric current
permeability of free spacepermittivity of free space
charge of the electron, e
triple point of waterabsolute zero
Boltzmann's constantk
amount of substance
molar mass of Carbon-12
Avogadro constant NA
luminous intensity
luminous efficacy of a 540 THz source
same as current SI

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