Understanding Sensors - An Analogy

In fact, the human body, for its proper functioning, depends on the five sensory organs – eye, ear, nose, tongue, and skin. The functioning of the human senses (sensory organs) is clearly defined – they take the information about external environment and transmit it to the brain for processing. The brain then directs the body on the further course of action. As a result, the proper functioning of the sensory organs is of critical importance for the safety and well-being of the human body.

Human senses and Machine sensations

Over the years, a plethora of specialty sensors have been developed that can detect a wide variety of physical or chemical properties.

• Physical sensors that play a role in vision, hearing, and touch, sense and convert physical quantities such as light, sound waves, pressure, and temperature into electrical signals.
• Chemical sensors play a role of taste and smell. Depending on the presence, concentration, and composition of various chemicals, it converts and detects electrical signals.
• Biological sensors are considered to be part of chemical sensors, but they detect the states or substances using biological properties that emit electrical and optical signals.
• There are high-sensitivity sensors that detect magnetism and radiation dose that cannot be detected by the human senses.

Sensors in industrial applications play the same crucial role, just like sensory organs in the human body. Process industries have a cluster of machines or systems and interconnected devices that depend heavily on sensors for their proper functioning. Sensors, networked within the process flow, have a continuous job of detecting, measuring, and transmitting electrical signals for any changes in their physical environment. The electrical signals are transmitted to a control system (a computer) that process the data and directs the process further.

With the continuous advancement of society, the process flow and control machinery have evolved too. In fact modern day machines now come with a highly sensitive and wide option human interface for control and monitoring purposes. Sensing technology is so automated that it can pick human desires and intentions and take the process further.

So just as the sensory organs in human body look after the various tasks and are a critical element for life to function properly, sensors play the same role in the process industry by keeping a check on the various processes parameters for continuous functioning.

Five senses	Sight	Hearing	Smell	Taste	Touch
As behavior	-See the thing -Feel the light	-Listen the sound -Feel the shaking -Take the balance	-Smell the thing	-Feel the taste	-By touching, feel the heat, force, or texture
Sensory organ as human	Eye	Ear	Nose	Tongue	Skin
Typical sensors as machinery	-Image sensor -Light intensity sensor	-Acoustic sensor -Ultrasonic sensor	-Gas component sensor	-Liquid component sensor	-Tactile sensor -Pressure sensor -Temperature sensor -Humidity sensor -Displacement sensor

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