There is a wide variety of industrial sensors on the market
and choosing the right sensor for your application can be difficult.
Industrial sensors cover almost all categories of sensors,
including proximity, position, speed, level, temperature, force and pressure.
Applications can be found in a wide variety of fields, including industrial
process control, energy, aviation, security, automotive, sanitation and
building automation.
Sometimes, sensors form key elements of products and
solutions. These are important parts of the product that define the quality,
efficiency and safety of the intended application. From semiconductor chips and
transmitters to complex systems, there are sensor solutions and technologies
throughout the value chain. This article analyzes the characteristics of the
sensors used in the control and monitoring of industrial processes, including
wireless sensors, and some of the leading manufacturers of industrial sensors.
Industrial Process
Control:-
The control of industrial processes includes the monitoring
and control of machines, systems and processes in a number of industries
including chemical, pharmaceutical, biotechnology, energy, water, oil and gas,
plastics, paper and food and beverages. Modern industrial processing and
manufacturing systems are automated to consume raw materials and energy
efficiently. There are many parameters to monitor and control, including
pressure, temperature, level, flow rate, humidity, dust, corrosive substances,
explosives, liquids and gases.
Sensors are the first element of process control and
measurement systems. Precise control and precise displacement / position
measurements on very small scales, such as nanometers and pico-meters, have
become increasingly important over the years.
The main performance criteria for industrial sensors are
sensitivity, resolution, miniaturization, long-term stability, thermal drift
and energy efficiency.
Some sensors used for
the control of industrial processes:-
Proximity sensor:-
These can be mechanical, optical, inductive and capacitive.
Widely used in industrial automation, such as the transport line for counting
and jamming, safety interlocking and machine tool for sequencing. It is also
used to detect the presence of an object.
Inductive and capacitive proximity sensors are usually short
range but very robust and reliable. Inductive sensors use magnetic properties
to detect the presence of metallic objects. Capacitive sensors
are commonly used to detect capacitance due to non-metallic objects.
Position sensor:-
This includes linear variable differential encoders and
transformers (LVDT). An encoder is typically a digital sensor used to provide
position feedback for an actuator. These consist of glass or plastic discs that
rotate between a light source (LED) and a pair of photo detectors. Plastic
discs are alternately encoded between light and dark, creating pulses as the
disc rotates.
The LVDT consists of a magnetic core that moves in a cylinder. Commonly used
for position feedback in servo mechanisms, automatic measurements and many
other industrial and scientific applications.
Force sensor:-
Force and pressure sensors generally act as transducers.
These generate signals based on the pressure exerted on them. The force
detection resistors are two-pin force sensors whose resistance changes when
mechanical force, pressure or tension is applied to the sensor surface. The TE
Connectivity FN3050 sensor is a rugged load cell ideal for process industry and
test bench applications.
Vibration /
acceleration sensor:-
Ceramic piezoelectric sensors or accelerometers are used
more frequently to detect vibrations. 3-axis accelerometers are used in mobile
systems, cars, turbines and airplanes. Provides information about vibrations
and position data. Inertial measurement units often use gyroscopes and
accelerometers to measure linear and angular movement. They are widely used for
navigation and orientation of airplanes and missiles.
Level sensor:-
This sensor is very common in the control of industrial
processes. The selection of an appropriate level sensor depends on the size and
shape. Industrial process control includes hydraulic and optical level sensors,
from simple limit value detection to precision level continuous detection.
Hydrostatic sensors can be installed as underwater sensors, located in the
fluid or threaded for fixing to the outer wall of the tank.
