Double acting pneumatic cylinder operation using 5/2 direction control valve and PLC

 Problem Statement: -

A heavy door is to be opened or closed by a double-acting cylinder. This door will open or close with two push buttons, one push button is located inside and another push button is located outside. Draw a Ladder Diagram for the Giving Condition.

a) The push button should only work when the door is either fully open or fully closed.

Solution: -

Number of inputs = 4

PB1: Inside push button

PB2: Outside push button

L1:  Limit switch located at closing position.

L2:  Limit switch located at open position.

 

Number of outputs = 2

Y1: Left Solenoid of 5/2 control valve

Y2: Right Solenoid of 5/2 control valve

Pneumatic Circuit Diagram:

Answer - (a): -

 Number of inputs = 4

Possibilities = 2⁴ =16

Description: -

Initially, as the door is fully closed the L1 limit switch is pressed (L1=1 & L2=0), the door will only open when any one of the push buttons is pressed (PB1 =1 & PB2=0 OR PB1=0 & PB2=1)

It is not possible that both the Limit switches L1 & L2 are pressed at the same time   (L1=1 & L2=1).

Both the switches are unpressed (L1=0 & L2=0), which means the door is neither fully opened nor fully closed

As the door is fully closed the L1 limit switch is pressed (L1=0 & L2=1), the door will only open when any one of the push buttons is pressed (PB1 =1 & PB2=0 OR PB1=0 & PB2=1).

Hence, Y1= (L1) (L2)’ (PB1)’ (PB2) + (L1) (L2)’ (PB1) (PB2)’

               = (L1) (L2)’ [(PB1)’ (PB2) + (PB1) (PB2)’]

 

             Y2= (L1)’ (L2) (PB1)’ (PB2) + (L1)’ (L2) (PB1) (PB2)’

               = (L1)’ (L2) [(PB1)’ (PB2) + (PB1) (PB2)’]

 

Note: - Above application may be different from actual application. This example is only for explanation purpose only. We can use this concept in other examples also. All parameters and graphical representations considered in this example are for explanation purpose only, parameters or representation may be different in actual applications. Also, all interlocks are not considered in the application.

                                                                                            Written by Subham Prajapati