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Welcome
Resource Persons
Mr. Mukut KalitaSensors and data acquisition

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Sensor is a device that responds to some types of the input from
the environment such as heat,light,motion,
temparature,pressure,moiture etc.Sensors are used to switch
currents and voltages.
Sensor converts stimuli such as heat, light, sound and motion
into electrical signals. These signals are passed through an
interface that converts them into a binary code and passes this
on to a computer to be processed

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Basically two types of sensor
Analog Sensor
Digital Sensor
Analog Sensors
PT 100
RTD
Thermocouple
Digital Sensors
Photo Sensor
Proxy Sensor

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An inductive sensor is a device that uses the principle of electromagnetic induction to detect or measure objects.
An inductor develops a magnetic field when a current flows through it; alternatively, a current will flow through a
circuit containing an inductor when the magnetic field through it changes.
In electronics, a Schmitt trigger is a
comparator circuit with hysteresis
implemented by applying positive
feedback to the non inverting input
of a comparator or differential
amplifier. It is an active circuit
which converts an analog input
signal to a digital output signal.

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Noncontact capacitive sensors work by measuring changes in an electrical property called capacitance.When a
voltage is applied to the conductors, an electric field is created between them causing positive and negative charges to
collect on each object

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Through Beam type
Sensor
Emitter and receiver at
different location
Retro Reflective type
Sensor
Emitter and receiver
located at the same
location and reflective
plate is used
Diffuser Type Sensor
Emitter and receiver
located at the same
location
Photoelectric Sensor consists primarily of an Emitter for emitting light and a
Receiver for receiving light. When emitted light is interrupted or reflected by
the sensing object, it changes the amount of light that arrives at the Receiver. The
Receiver detects this change and converts it to an electrical output.

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Problem Statement:
There is liquid can filling line where we required to measure the nos of can filled per hour and also
required to create a report at the shift end
Which Sensor we can use for the
same??
Diffuser Type Product Counter

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Four common Types of temperature measurement
Sensor
•Thermistor Negative Temperature Coefficient
•RTD Resistance Temperature Detector
•Thermocouple
•Semi conductor based Sensors

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An RTD works by using a basic principle; as the
temperature of a metal increases, so does the
resistance to the flow of electricity. An electrical
current is passed through the sensor, the resistance
element is used to measure the resistance of the
current being passed through it
RTDs of different shapes as per the applications

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Thermocouple is a sensor used to
measure temperature. Thermocouples are
made with two wires of different metals,
joined together at one end to form a
junction. As the temperature changes, the
two dissimilar metals begin to deform,
causing a change in resistance

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In Industry J and K types are used in most cases

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A thermistor is a resistance thermometer,
or a resistor whose resistance is dependent
on temperature. A PTC thermistor works a
little differently. When temperature
increases, the resistance increases, and
when temperature decreases, resistance
decreases. This type of thermistor is
generally used as a fuse.

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Semiconductor temperature sensors commonly use a band gap element which
measures variations in the forward voltage of a diode to determine temperature. To
achieve reasonable accuracy, these are calibrated at a single temperature point,
typically 25 °C

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Different Types of Sensors used for level
measurement
•Optical Sensor
•Vibrating or tuning Fork
•Ultrasonic
•Float
•Capacitance
•Radar
•Conductivity or resistance

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Optical sensors work by emitting light rays where
emitter emits the signals and the receiver receives the
signal where basis on the obstruction of the lights there
will be current flow and potential drop and basis on which
the system works

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The sensor has a magnet and an electromagnet
fixed on the vibration plate. When current is
applied to the electromagnet, repulsive force of
the magnet causes the plate to vibrate.
When the material covers the plate, vibration
decreases, causing lower voltages to be induced
in the electromagnet. The sensor detects the
voltage change to determine material presence.

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Ultrasonic sensors work by emitting sound waves at a
frequency too high for humans to hear. They then wait for the
sound to be reflected back, calculating distance based on the
time required. This is similar to how radar measures the time it
takes a radio wave to return after hitting an object

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Float switch. A float switch is a type
of level sensor, a device used to detect
the level of liquid within a tank.One pattern
uses a reed switch mounted in a tube;
a float, containing a magnet, surrounds the
tube and is guided by it. When
the float raises the magnet to the
reed switch, it closes.

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When functioning as level sensors,
capacitors work by
processing capacitance with reference to
the dielectric constant of the material being
measured and the voltage being used to
complete the circuit

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In radar level measurement, microwaves
transmitted by the antenna system of
the radar sensor to the measured product,
reflected by the product surface, and
received back by the antenna system. The
time from emission to reception of the
signals is proportional to the level in the
vessel.

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Conductivity level switches are sensors with an electrical
contact output at a specific liquid level. Applications include
ponds, reservoirs, sumps, pharmaceuticals, closed vessels and
open tanks. Dual Point Level Switch maintains liquid level high
and low limits.

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The working principle of the weight sensor depends on
the conversion of a load into an electronic signal. The
signal can be a change in voltage; current otherwise
frequency based on the load as well as used circuit.

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Rotary encoder, also called a shaft encoder, is an
electro-mechanical device that converts the angular
position or motion of a shaft or axle to analog or
digital output signals.The output of an
absolute encoder indicates the current shaft
position, making it an angle transducer.

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Data acquisition or DAQ is a process that measures physical or
electrical phenomena like sound, pressure, temperature, voltage,
current etc. A typical DAQ system consists of sensors, DAQ
measurement hardware, and a computer that has programmable
software
Mainly Two systems quite
popular for data acquisition
system in industry
DCS
SCADA
While a DCS emphasizes
process-level operations,
a SCADA is event-
driven and prioritizes data
gathering. A DCS delivers data
to operators, and at the same
time, a SCADA concentrates
on the acquisition of that data

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Key components for
SCADA system
•Sensors
•Actuators
•PLC
•RTU
•HMI
•Communication
Modules
•HMI
•SCADA

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