Introduction to Industrial Automation

Example 4.6:  Different Design of the Example 4.5 State Diagram

The pair of two machines must start operating successively by pressing the same button b two 

times. As shown in Figure 4.16, the system goes from the rest state S

0

 to the state S

1

, where only 

the machine M operates, through the pushbutton signal b. The system remains in this state for 

as long as the pushbutton is not released. Just after releasing the pushbutton b, the condition 

b

 is satisfied, and hence the system goes to state S

2

, which is identical to the state S

1

, which 

means that only the machine M operates. The second pressing of the pushbutton b similarly 

causes the transition to state S

3

, and subsequently the releasing of the pushbutton b leads to 

the state S

4

, where both machines are in operation. The rest of the state diagram is similar to 

that of Figure 4.14.

N

A

R

B

Α

Β

B

A

B

A

B

N

M

s

2

s

2

A

b

b

1