Introduction to Industrial Automation

 

◾

  Introduction to Industrial Automation

selecting the suitable directional valve for the double-acting cylinder, design the required 

electric automation circuit. 

S

1

S

2

S

3

M

Conveyor belt

Standby indication

Standby in button

Standby out button

Position 1 

Position 2 

Position 3 

S

4

S

5

 5.13. A simple robotic mechanism operates with the assistance of two double-acting cylinders C

1

 

and C

2

. The extension of cylinder C

1

 causes the rotation of the robotic arm by 180

o

 from the 

right position P

1

 to the left position P

2 

while transferring an object. The extension of cylinder 

C

2

 causes the closing of the griper and hence the tightening of an object. The sufficient tight-

ening of the object is detected by the pressure sensor PR and only then can the arm rotation 

start. The two terminal positions of the arm are detected by the corresponding proximity 

switches PS

1

 and PS

2

. The robotic mechanism starts to operate through a two-position rotary 

switch RS

0-1

 and transfers objects continuously, as long as they are placed into the griper in 

position P

1

. The import and export of objects in the griper is done automatically by another 

machine and hence it will ignore what the robotic mechanism does if there is no object. After 

selecting the required additional electro-pneumatic equipment (directional control valves, 

sensors, etc.), design the electric automation circuit applying the state diagram method, in 

order for the position-step diagram of the figure to be realized iteratively.

C

1

PS

1

PR

P

2

P

1

C

2

PS

2

 

 

 C

1

C

2

Position P

2

Position P

1

Griper closed

Griper opened

1 2 3 4

 5.14. The figure shows a pneumatic set-up for bonding two parts of a final product. The cylinder 

C

1

, after its extension, applies the required liquid epoxy glue during the retraction phase 

with the simultaneous operation of the small glue pump M. Then, the cylinder C

2

 com-

presses the two pieces in order to be bonded. A technician puts two pieces for bonding 

that are detected by the corresponding proximity switches PS

1

 and PS

2

. With this fact as 

a condition, the bonding procedure can be triggered by pressing a push-button instantly 

and then the position-step diagram of actions must take effect. Note that when the cylinder 

C

2

 pushes the left piece, the switch PS

1

 stops to be energized. After selecting the required 

additional electro-pneumatic equipment (cylinders kind, directional control valves, sensors, 

etc.), design the electric automation circuit applying the state diagram method.

---

Elements of Electro-Pneumatic Components 

◾

 

191

C

1

C

2

In

Out

Μ

Μ

PS

1

1 2 3 4 5

OFF

ON

PS

2

C

1

C

2

 5.15. A machine M

1

 processes objects which arrive via a conveyor belt M

2

. The last enters within 

the machine M

1

 and exits on the other side, while the processing is performed in motion.

    Sometimes the processing of an object fails. In such a case, the faulty object is detected 

by the specific photoelectric window PE and then the following actions must take effect:

 

a.  The conveyor belt M

2

 stops, and the rejected object is transferred from the point K to the 

point L through the sequential activation of the three cylinders C

1

, C

2

, and C

3

 in order 

to be re-processed according to the position-step diagram of the figure.

 

b.  With the rejected object at point L, the conveyor belt starts to operate again. Suppose 

that there is no possibility for collision with another non-processed object.

 

c.  The machine M

1

 continues to operate during restoration of the rejected object in order 

for the raw materials to be at a suitable temperature. 

    The whole system starts by an instant signal from the START button. Then, a time period 

of 80 sec must follow for warming-up the machine M

1

 (power supply of existing resistors). 

At end of this period, M

1

 and M

2

 operate automatically. The system stops after an instant 

signal from a STOP button, but only if there is no evolution of a faulty object restoration.

    After selecting the required additional electro-pneumatic equipment (cylinders kind, 

directional control valves, sensors, etc.), design the electric automation circuit applying the 

state diagram method.

Μ

2

Κ

 

L  

PE

C

1

C

2

Μ

2

C

3

 

PE

C

1

C

2

C

3

Μ

2

1 2 3 4

In

Out

Off

On

= Rejected object 

= Good object 

Μ

1

---

http://taylorandfrancis.com

---