Generalized measuring System
Generalized Measuring System
Common elements of system:
•
Primary
Sensing Element
•
Variable
Conversion Element
•
Variable
Manipulation Element
•
Data
Processing Element
•
Data
Transmission System
•
Data
Presentation Element
Primary Stage (or) Primary Element:
•
The primary sensing element receives
signal of the physical quantity to be measured as input.
•
It converts the signal to a suitable
form (electrical, mechanical or other form), so that it becomes easier for
other elements of the measurement system, to either convert or manipulate it.
Variable Conversion Element:
•
Convert
a signal into a signal which is suitable to the final stage.
•
Selective
filtering to remove unwanted input components.
(Not necessary for all
instruments)
Variable Manipulation Element:
•
Variable manipulation element
manipulates and amplifies the output from variable conversion element.
•
It also removes noise (if present) in
the signal.
Data processing Element:
•
Data processing element is an important
element used in many measurement systems. It processes the data signal received
from the variable manipulation element and produces suitable output.
•
Data processing element may also be used
to compare the measured value with a standard value to produce required output.
Data Transmission System:
•
Data Transmission System is simply used
for transmitting data from one element to another.
•
It acts as a communication link between
different elements of the measurement system.
•
Some of the data transmission elements
used is cables, wireless antennae, transducers, telemetry systems etc.
Data Presentation Element:
•
It is used to present the measured
physical quantity in a human readable form to the observer.
•
It receives processed signal from data
processing element and presents the data in a human readable form.
•
LED displays are most commonly used as
data presentation elements in many measurement systems.
Ex:-Indicating Thermometer:
Primary stage- Heat
is converted into fluid displacement by the thermometer sensing bulb.
Secondary stage –
bourdon tube and link
Manipulating stage- Gear
Final stage- pointer and scale