Several measurement systems are in use today. Before measuring a physical quantity, it is necessary to understand the working of the measurement system used.
Generalized measurement system is a system that is comprised of the typical elements of a measurement system. It helps to understand how a measurement system works.
Components of Generalized Measurement System:
A generalized measurement system consists of the following components:
- Primary Sensing Element
- Variable Conversion Element
- Variable Manipulation Element
- Data Processing Element
- Data Transmission System
- Data Presentation Element
In addition to the above components, a measurement system may also have a data storage element to store measured data for future use. As the above six components are the most common ones used in many measurement systems, they are discussed in detail below:
1. Primary Sensing 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.
2. Variable Conversion Element:
Variable conversion element converts the output of the primary sensing element to a more suitable form. It is used only if necessary.
3. Variable Manipulation Element:
Variable manipulation element manipulates and amplifies the output of the variable conversion element. It also removes noise (if present) in the signal.
4. 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.
5. 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 are cables, wireless antennae, transducers, telemetry systems etc.
6. 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.
For better understanding of generalized measurement system, refer the diagram above.