Introduction to Industrial Automation

Figure 7.73  A semiautomatic drilling machine and the PLC controlling its operation.

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Basic Programming Principles of PLCs 

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  7. As soon as S

0

 is activated, the drilling head and the protective cover return simultaneously 

to their initial position. Then the machine is ready to accept a new item.

  8. If at any time, either the two “stop drilling” buttons are pressed simultaneously or the 

“Stand-by OFF” button is pressed alone, the process stops and the two pistons return to the 

“up” position.

  9. For the connection diagram of I/O devices in the PLC and the listed addresses, the required 

Boolean language program is as follows:

A

I0.1

A(

O

I0.3

O

I0.5

)

A(

O

I0.0

O

Q4.1

)

=

Q4.1

A

Q4.1

A

I2.1

A(

A

I0.2

A

I0.4

O

A

Q5.4

A

I2.2

)

AN I2.0

=

Q5.4

A

Q5.4

A

I2.2

=

Q5.1

A

Q5.1

=

Q4.4

BE

The corresponding program in LAD language is shown in Figure 7.74.

Bowling automation. In Figure 7.75 an automated runway of the well-known bowling 

game operated and controlled by a small PLC is shown. Of course, it is not an industrial 

application but since it is familiar to anybody and presents interesting automation features 

it can be considered as a small automation project. In each game (coin throw) the player has 

the right to do 12 double attempts. Any double attempt means that the player can roll the 

LAD

I 0.3

I 0.2

I 0.4

I 2.2

I 2.1

Q 4.4

Q 5.1

Q 4.1

Q 4.1

Q 4.1

I 0.0

I 0.1

I 0.5

I 2.0 Q 5.4

Q 5.4

I 2.2

Q 5.4

Q 5.1

LAD

I0.3

I0.2

I0.4

I2.2

I2.1

Q4.4

Q5.1

Q4.1

Q4.1

Q4.1

I0.0

I0.1

I0.5

I2.0

Q5.4

Q5.4

I2.2

Q5.4

Q5.1