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Prepared by

Dr. Mohiy Bahgat

Faculty of Engineering

Helwan University

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Practical Systems1. Central Heating System.

2. Mixing Process Application.3. Packing Application.4. Testing an Automatic Door Control System.5. Filling / Draining Control Operation.6. Flag Operated Packaging System.7. Automation of Parking Garage.8. Sequence Control Process.

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9. Product Packaging.10. Parts Sorting.11. Robot Movement Control.12. Overhead Crane Control foe Degreasing Pro.13. Drilling Control Operation .14. Automatic Control of Warehouse Door.

15. Automatic Lubrication of a Gear.

16. PBC Packing Conveyor.

17. Conveyor Belt Motor control.

18. Ball Sorter Mechanism.

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Programming Examples

1. A signal lamp is required to be on if :A pump is running.

And

The pressure is satisfactory.

Or The test lamp is closed.

Pump

X400

Presu.

X401

Lamp

Y430

Test

X402

Step Instruction

0 LD X4001 AND X401

2 LD X402

3 ORB

4 OUT Y430

5 END

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2. A machine has 4 sensors to detect the

safety and is required to be off if :

Any of the sensors gives input. when the machine is stop, an alarm is sound.

Step Instruction0 LDI X400

1 ANI X401

2 ANI X402

3 ANI X403

4 OUT Y430

5 LD X400

6 OR X401

7 OR X402

8 OR X403

9 OUT Y431

10 END

X400

X401Mamchine

Y430

X400

X402

X403

X401

X402

X403

AlarmY431

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Central Heating SystemConsider a central heating system with thefollowing features :

The boiler is thermostatically controlled and

supplies the radiator system in addition to a hotwater tank.

Pumps are used to supply hot water to either or

both the radiator and the tank according to thedesired sensors.

The whole system is controlled by a clock to

operate a certain time a day.

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Boiler Temp.

sensor

Motorized

Pump

M1

M2

Boiler

Motorized

Pump

Radiator

System

Room

Timers

Hot water tank

Temp. sensor

Hot water

tank

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Mixing Process Application Automatic mixing processes of liquids and other

compounds in the chemical and food industries are very

common.

The mixing station goal is to mix two liquids for a

specified time and then output the final product to a

storage tank.

The system consists of :

1. Two level sensors to monitor the flowing of the

liquids into the tank.2. Three solenoid valves to control the flow of liquids.

3. A motor connected to an agitator to mix the liquids

into the tank.

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Mixing

Station

LS1

LS2

Level Sensors

VA1

VA2Input Valves MS1

Motor & Agitator

Mixing Tank

VA3 Output to Storage Tank

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The sequence of events for this automatic mixing process will

be as follows :

1. Open valve 1 until level 1 is reached for the first liquid .2. Then close valve 1 .

3. Open valve 2 until level 2 is reached for the second

liquid .

4. Then close valve 2 .

5. Start the motor and agitate to mix the liquids into the

tank for a specified time .

6. Then stop the motor .

7. Open valve 3 up to a specified time to empty the mixed

product to a storage tank .

8. Then close valve 3 .

9. Repeat or end the mixing process as required .

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PACKING Application

Consider the following packing machine,where it is required to pack 6 objects in a

box and then pack 12 objects in another

box in another path as shown :

6 in box

12 in box

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Testing an Automatic Door

Control System

A door system for trains is tested by automatic

opening and closing the doors about 1000 times.

On every fifth closing of the doors, a pneumatic

cylinder out-strokes to simulate an obstruction.

The cylinder will remain in the obstruction

position while the doors attempt to close three

times.

After the third attempt, the cylinder in-strokes to

allow the doors to be fully closed.

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Rails

Cylinder

Obstruction

Doors

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Filling / Draining Control

Operation

Charge and discharge of a reservoir is a

common process in industry as well as a need

for mixing two or more substances usingautomated valves.

Consider the charge and discharge system

displayed in figure, it is required to :

a) Operating the process in accordance to

the displayed operating panel.

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b) Pressing (T1) on the operating panel, willopens valve (V1) to start filling up withrunning the motor(M) until reaching (S1).

c) When completing filling up, valve (V1)closes, motor stops and valve (V2) opensto start emptying until reaching (S2) toclose (V2).

d) It is required that the reservoir has to be

filled up and emptied four times with the

same cycle before activating the End-

lamp.

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FLAG OPERATED SIMPLE

PACKAGING SYSTEM

Consider the conveyor system displayed in

figure :

It is required that the components to be

channeled down route (A) for 5 minutes andanother 2 minutes down route (B) bycontrolling the flap (F).

A start and stop facility is required to start

and end the process.

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The flap (F) is controlled by a piston via pivotlinkage.

Draw the system ladder logic diagram showing

the addresses of all inputs and outputs and

write down the corresponding statement list

program using the Mitsubishi PLC notation.

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Automation of Parking Garage

Consider a simple system that can control 100car at the maximum.

Each time a car enters, PLC automatically

adds it to a total sum of other cars found in

the garage.

Also, each car that comes out will

automatically be taken off.

When 100 cars park, a notifying signal that the

garage is full will turn on.

Otherwise a Vacancy signal should turn on.

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SEQUENCE CONTROL PROCESS

Consider the motor movement control system

displayed in figure with the following features :

1. When the start button is pressed, the

motor will move from left to right.

2. When LS2 is on, the motor stops, delays for

5 sec. and then moves back to home.

3. When LS1 is on, motor cuts off signifying

that the sequence is completed

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Motor Right

Motor Left

LS1 LS2

HOME

StartStop

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Product Packaging

Consider the packaging system shown in figure

with the following features :

1. By pushing START key a Flag1 is activated.

2. Resetting depends only on a STOP key.

3. When started, motor of a conveyor for

boxes is activated. The conveyor takes a

box up to the limit switch, and a motor

stops then.

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4. Starting the product conveyor is activated

by a limit switch when a box is detected.

5. The presence of a box allows counter to

count 10 products.

6. On activating the conveyor with boxes, a

limit switch resets counter to be ready to

count 10 products again.

7. Operations repeat until STOP key is

pressed.

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