CHAPTER 1ELECTRICAL CONTROLLER

EQUIPMENT

BY:Salsabila Ahmad

ELECTRICAL CIRCUIT BASIC

4 ELECTRICAL BASICS POWER SUPPLY INPUT DEVICE

Input Controller Equipment CONDUCTOR OUTPUT DEVICE

Output Controller Equipment

POWER SUPPLY

Definition: A device which supplies energy needed

to create an electrical current

INPUT DEVICE DEFINITION 2 TYPES OF INPUT DEVICE

Mechanical input device Solid state proximity device

ELECTRICAL SWITCHING Basic Principle of Electrical Switching Types of Contacts How do These Contacts Work?

DEFINITION: A device which allows/ controls the flow

of current in a circuit These devices are known as“ELECTRICAL CONTROLLER EQUIPMENTS” Provides Electrical Switching

MECHANICAL INPUT DEVICES

Definition: An input device with a

mechanical contact

SOLID STATE PROXIMITY DEVICES

Definition: An electronic input device which

needs power to be able to operate

EG Various types of sensors

EXAMPLE OF MECHANICAL INPUT DEVICES Contact Relay Push button Limit Switch Selector Switch Toggle Switch Temperature Switch Pressure Switch Solenoid Switch Induction Motor Controller

PROXIMITY SENSORS CATEGORY

Proximity sensors inductive

capacitive dielectric type

conductive type

ultrasonic

optical diffuse reflective type

retro reflective type

thru beam

fiber optic sensor

color mark sensor

encoder sensor

RELAY

2 TYPES OF RELAY: EMR SSR

ELECTROMAGNETIC RELAY (EMR)

Definition: An EMR is an electromagnetic

device composed of a frame/core, electromagnet coil and contacts (move and fixed)

Based on simple electromagnetic principle

SOLID STATE RELAY (SSR)

HOW IT OPERATES? Operates similarly to EMR, but

with no mechanical contact. Employ semiconductor switching

elements such as thryristors, triacs, diodes and transistors.

Employ optical semiconductors called photo couplers to isolate input and output signals.

Photo couplers change electrical to optical signals and relay the signal through space.

CHARACTERISTICS OF EMR AND SSR

EMR SSR

slow speedwears out easilyNoisyCheap

high speed, high frequency for switching operationsno failure due to wear out, since no mechanical contactslittle noiseExpensive

Most common relay symbols used in electrical machine diagram

Normally open (NO)

Normally close (NC)

Coil

RELAY SYMBOLS

BASIC PRINCIPLE OF ELECTRICAL SWITCHING

A situation of breaking and open an electrical circuit

Or to direct current from one conductor to another.

The PLC is the solution to today’s electrical switching requirements where it is able to solve

complex switching requirements.

2 TYPES OF CONTACT

NO NC

HOW DO THESE CONTACTS WORK?

Once coil is energized, the contact will change state NO NC NC NO

SOLENOID SWITCH

Use concept of magnetic flux for armature/plunger to move

Produces linear mechanical motion

DEFINITION pushbutton-type operator Have one set or more contact/spring Mostly have a set of normally open

(NO) and normally closed (NC) contact

PUSH BUTTON

CONCEPTS OF OPERATION

Pushing the operator causes the contacts to change state

Spring causes switch operator to automatically return to it’s natural state when it is released.

NO NC NONC NO NC

natural state change state automatic return

a switch with this return spring action, is called a momentary switch.

APPLICATIONS

Frequently used in industrial applications to control functions such as starting and stopping

the machine’s operation With a safety nature. Why?

SCHEMATIC SYMBOLS FOR PUSH BUTTON

Normally Open Contact

Normally Closed Contact

Similarly to pushbutton, but instead of pushing, you rotate a knob

may be designed to stay in a selected position or may have a momentary action

selector switch that stays in a certain position is called a maintained switch.

SELECTOR SWITCH

APPLICATION Widely used in industrial applications

for switching mode of operation to turn the main power on and off to select between AC or DC output.

Some requires key (authorized person) to turn on for safety reason.

SCHEMATIC SYMBOLS FOR SELECTOR SWITCH

Normally open contact

Normally close contact

Selector switch with two contacts

TOGGLE SWITCH

Toggle switch is a maintained switch

INDUCTION MOTOR CONTROLLER Commonly used micro-controllers

PROXIMITY SENSORS

INDUCTIVE PROXIMITY SENSOR

Sense only metallic objects e.g. steel, iron, aluminum, tin,

copper etc Has limited sensing range

range affected by the type of metal sense

CAPACITIVE PROXIMITY SENSOR

sense all material with mass. operation for both dielectric and

conductive type are the same The dielectric type works best for

high density material Low density material (e.g. paper,

foam etc) do not cause a detectable change in dielectric.

The conductive type works best on electrically conductive material e.g. metal or water-based

material)

ULTRASONIC SENSOR

Use ultrasonic technology How does it works?

CONCEPTS OF ULTRASONIC SENSOR Use an ultrasonic “ping” sent from

sensor to target Sensing area is a funnel shape area Therefore, target must be located directly in

front of sensor

When echo is returned, sensor detects target by measuring time delay between transmitted ping and returned echo sensor calculate distance between

sensor and target

Do not work well on cloth, foam rubber

since good absorber of sound waves

Works best on high density material

where sound waves reflects best

DIFFUSE REFLECTIVE

Emitter and receiver located in same housing

Light emitted is received when the object is present

Works well on glossy target but not transparent

Emitter and receiver

Emitter and receiver located in same housing.

Light emitted is received when the object is absent.

Does not work well with glossy target. Why?

Because glossy target acts like a reflector

Emitter and receiver

reflector

RETRO-REFLECTIVE

Emitter and receiver is located in different housing

Sense the object’s present when it passes through between emitter and receiver

where it stops the light from hitting receiver

emitter receiver

THRU-BEAM

Use plastic and glass fibers to carry lights

Available in both thru beam and reflective

Thru-beam

Reflectorobject

FIBER OPTIC

A special type of diffuse reflective optical sensor that can differentiate between colors

some can detect contrast between colors.

Typically used to check labels and sort packages by color mark.

COLOR MARK

ENCODER

Used for position feedback and some for velocity feedback

Two main types Incremental absolute

CONDUCTOR

Definition: A medium that connects all the

components and allows current to flow.

Examples: copper wire bread board

OUTPUT DEVICE

DEFINITION A component that will produce a

desired output. It is also referred to as a load.

COIL Can represents various forms of

output including Motor Light Pump Counter Timer Relay

TIMER most common symbol for

displaying timer function is in block diagram uses a box shape to display the

timer function Sometimes, timer is displayed

in coil format symbol

CHARACTERISTICS OF TIMER

Timers typically have one or two input

Timer with one input has functions as a timer enable input. When input ‘high’, the timer begins timing

A timer with 2 inputs has additional functions which is used to reset the timer accumulated time to zero when the second input is ‘high’

Every timer has a time base Typically; 1 sec, 0.1 sec and

0.01sec.

HOW TIMERS ARE IDENTIFIED? Each timer will have number to

identify it There are two parameters for timer

timer number Used to identify timer e.g. Timer

0, Timer 2. Preset value

Is the delay time set for the timer

TIMER’S PROGRAM

There are still many similarities in the way the timers are programmed even when PLC are different brand

Let say the time base of a timer is 0.1 second

Therefore, if a programmer entered 50 for the number of delay increments

What is the timer’s delay? the timer would have a 5-second

delay. 50 x 0.1 sec = 5 sec

Has one input Timer enabled if the

input logic is ON Timer reset if the input

logic is OFF Maximum value 9999

TMR TIMER0

T0

K40

INPUT

TMR

TMRA Has two inputs Timer starts timing

when ENABLE is ON Timer stops when

ENABLE is OFF without resetting the current value to 0

TMRA TIMER2

T2

K50

ENABLE

RESET

The timer resets when RESET is ON The timer is enabled to start when

RESET is OFF

What is it? What is it characteristics? How does it works? Testing your understanding….. Testing your imagination…..

used to capture and store number of occurrence

COUNTER

CHARACTERISTICS

set to some preset number value when this value of input pulses has

been received, it will operate its contacts

Let say the counter is set for 10 pulses, then when 10 pulse impulses have been received, the counter contacts will close

When there is a input transition for X0 from OFF to ON, counter starts counting

When the RESET is ON, the counter resets to 0

COUNTER PROGRAM

CNT COUNTER0

CT0

K5

INPUT

RESET

X0=sensor/ toggle switch

CT0

X1

OUT1 Counter starts counting when there is

an input transition X0 from OFF to ON

When the RESET is ON the counter resets to 0

MOTOR In PLC, motor can only be

controlled for power (ON/OFF) direction (CCW/CW) preset speed

TYPES OF MOTOR

DC motor type wound fieldpermanent magnetelectronics commutation

dc motors

AC motor type induction motorssynchronous motor