Magnetic ContactorMagnetic Contactor For handling large

current and voltage.

Can be used for interlock to prevent false and dangerous operations.

Magnetic Contactor Magnetic Contactor CircuitCircuit

Manual Operated Manual Operated SwitchesSwitches

Controlled by hand Include toggle

switch, push button, selector switch, etc.

Selector Switch CircuitSelector Switch Circuit

SwitchesSwitches DIP Switch Limit Switch

Limit Switch CircuitLimit Switch Circuit

For Starting For Starting and stopping and stopping a motor in a motor in forward and forward and reverse with reverse with limit switch limit switch providing providing over-travel over-travel protection protection

Temperature SwitchesTemperature Switches Or called Thermostat, Or called Thermostat,

to sense temperature to sense temperature changes, actuated by changes, actuated by some specific some specific temperature changetemperature change

Pressure SwitchPressure Switch To control To control

pressure of pressure of liquid and gasliquid and gas

Actuated Actuated when a when a specified specified pressure is pressure is reached.reached.

Pressure Switch CircuitPressure Switch Circuit

Level SwitchLevel Switch

To sense the To sense the height of a height of a liquid.liquid.

A float is A float is attachedattached

The rising and The rising and lowering of lowering of the float trips the float trips the level the level switchswitch

Transducers and SensorsTransducers and Sensors

Transducer Transducer convert energy convert energy from one form from one form to another.to another.

Sensors are Sensors are transducer for transducer for detecting and detecting and measuring.measuring.

Sensors used in Sensors used in ManufacturingManufacturing

Proximity SensorProximity Sensor To detect the To detect the

presence of an presence of an object without object without physical contact.physical contact.

Inductive is Inductive is actuated by actuated by metal objectmetal object

Proximity SensorProximity Sensor

Inductive Proximity Inductive Proximity SensorSensor

Proximity Sensors Proximity Sensors ConnectionsConnections

HysteresisHysteresis

Capacitive ProximityCapacitive Proximity

Actuated by any Actuated by any dirt in their dirt in their environment.environment.

Usually Usually supplement to the supplement to the inductive inductive proximity sensor proximity sensor when there is no when there is no metal available metal available for the actuation.for the actuation.

Magnetic SwitchMagnetic Switch

A magnetic switch A magnetic switch also called reed also called reed switch, composed switch, composed of two flat contact of two flat contact sealed in a glass sealed in a glass tube.tube.

As a permanent As a permanent magnet magnet approaches, the approaches, the ends of the ends of the overlapped contact overlapped contact tab attract one tab attract one another.another.

Light SensorLight Sensor

PhotovoltaicPhotovoltaic cell converts cell converts light energy light energy directly into directly into electric energy.electric energy.

PhotoconductivPhotoconductivee cell also called cell also called photo-resistive photo-resistive cell. Light energy cell. Light energy falling on the cell falling on the cell will cause change will cause change in resistance in resistance

Photoelectric SensorPhotoelectric Sensor

Use a LED for the Use a LED for the light source and light source and phototransistor to phototransistor to sense the sense the presence of light.presence of light.

Two main types of Two main types of photoelectric :photoelectric : - Reflective - Reflective - Through Beam - Through Beam

Reflective TypeReflective Type

It is used to detect the light It is used to detect the light beam (visible, infrared, or laser) beam (visible, infrared, or laser) reflected from the target.reflected from the target.

Through BeamThrough Beam

It is used to measure the change of It is used to measure the change of light quality caused by the target light quality caused by the target crossing the optical axis. crossing the optical axis.

Features of Photoelectric Features of Photoelectric SensorSensor

Non contact Non contact detectiondetection – long – long service lifeservice life

Almost any Almost any materialmaterial – based – based quantity of light quantity of light receivedreceived

Long detection Long detection distancedistance – – reflective(1m), reflective(1m), through beam through beam (10m)(10m)

High response High response speed – speed – 50us50us

Color Color Discrimination – Discrimination – based on based on absorption of its absorption of its colorcolor

Highly accurateHighly accurate

Barcode TechnologyBarcode Technology

Bar code system consists of : bar code Bar code system consists of : bar code symbol, a scanner , and a decoder.symbol, a scanner , and a decoder.

Bar code symbol contains up to 30 Bar code symbol contains up to 30 characters encoded in a machine-characters encoded in a machine-readable form.readable form.

Bar code systemBar code system

Mostly based on UPC (universal Mostly based on UPC (universal product code)product code) UPC type (1 char)UPC type (1 char) Manufacturer or vendor ID (5 chars)Manufacturer or vendor ID (5 chars) Item number (5 chars)Item number (5 chars) Check digit (1 char)Check digit (1 char)

Barcode ScannerBarcode Scanner A light source illuminates the bar A light source illuminates the bar

code symbol, those bar absorb light , code symbol, those bar absorb light , and spaces reflect light.and spaces reflect light.

A photo detector collects this light in A photo detector collects this light in the form of an electronics signal the form of an electronics signal pattern.pattern.

The decoder received the signal and The decoder received the signal and converts these data into character converts these data into character data. data.

Ultra sonic SensorUltra sonic Sensor

An ultrasonic sensor An ultrasonic sensor operates by sending operates by sending sound waves toward sound waves toward the target and the target and measuring the time measuring the time it takes for the it takes for the pulses to bounce pulses to bounce back.back.

Its bounce back time Its bounce back time proportional to the proportional to the distancedistance

Strain/Weight SensorStrain/Weight Sensor A strain gauge transducer converts a A strain gauge transducer converts a

mechanical strain into an electric signal.mechanical strain into an electric signal. Strain gauge are based on the principle Strain gauge are based on the principle

that the resistance of a conductor varies that the resistance of a conductor varies with length and cross-sectional area.with length and cross-sectional area.

Temperature SensorTemperature Sensor

ThermocoupleThermocouple Most commonly used for temperature Most commonly used for temperature

measurement.measurement. It is a pair of dissimilar conductors It is a pair of dissimilar conductors

welded or fused together at one end welded or fused together at one end to form the “hot”, junction with the to form the “hot”, junction with the free ends available for connection to free ends available for connection to the “cold” or reference junction.the “cold” or reference junction.

When temperature difference occurs, When temperature difference occurs, a small dc voltage is generated.a small dc voltage is generated.

Non contact Non contact Temperature SensorTemperature Sensor

Infrared radiation from the object Infrared radiation from the object surface generates hot spot on the surface generates hot spot on the thermocouplethermocouple

Flow MeasurementFlow Measurement Converts the kinetic Converts the kinetic

energy that the fluid has energy that the fluid has into some other into some other measurable form.measurable form.

Turbine flow meter’s Turbine flow meter’s blades turn at a rate blades turn at a rate proportional to the fluid proportional to the fluid velocity. velocity.

Magnetic flow meter offers Magnetic flow meter offers no restriction to flow. A no restriction to flow. A coil set up a magnetic field, coil set up a magnetic field, if a conductive liquid flows if a conductive liquid flows through this magnetic through this magnetic field, a voltage is inducedfield, a voltage is induced

Velocity/RPM SensorVelocity/RPM Sensor

The output of a The output of a generator varies generator varies with the speed at with the speed at which the which the generator is generator is driven.driven.