Introduction to Industrial Automation

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Industrial Applications 

◾

 

401

10.23   The Shearing Machine of an Unfolded Aluminum Sheet

A machine M unfolds and launches aluminum sheet in a laminate cutting table in order to be 

cut by a shearing machine SHM into pieces of a specified length. The machine M can drive the 

metal sheet at two speeds; at a low speed by the activation of the relay C

1

, and at a high speed by 

the activation of C

2

. The length of the metal sheet is measured via a pulse encoder ENC which is 

rotating during the sheet motion. The correspondence between pulses and sheet length is 1 pulse = 

1 mm. It is desired for the machine to cut two possible lengths: 50 cm and 100 cm (Figure 10.23).

Operating specifications:

  1. The length selection is done via the selector switch SS

1-2

.

  2. The pieces of small (large) length are cut at a low (high) speed, respectively.

  3. When the desired length is achieved, the machine M stops and the shearing machine operates 

for 3 s. After 3 s passes, the cutting procedure continues by starting again the machine M.

  4. With the START signal the operation of the whole machine begins, while with the STOP 

signal it stops. If during the operation of the machine at any cutting length, someone changes 

the position of the selector switch SS

1-2

, there should be no change.

Write the required PLC program in any desired language.

Coil 1

Coil 2

Coil

2

Coil

1

Green

Green balls

box filled

Yellow balls

box filled

Yellow

S

C

S

P

RS

0-1

S

C

S

P

SS

‘6’

‘12’

‘G’

‘Y’

+24 V DC

+24 V DC

0 V

0 V

PLC

I1.0

I2.1

Q2.1

Q2.2

Q5.0

Q6.0

I2.2

I3.1

I3.2

I4.0

Inputs

Outputs