Ladder Program Example for Lifter Application

Ladder Program Example for Lifter Application

Ladder Program to carry parts to three positions using the
lift.
Control Specifications

The following operation should be performed
in this unit.

Study the required specifications and then create the
program and confirm the operation

Overall
control

  • When [PB1] (X20) on the operation panel is pressed, Supply command
    (Y0)
    for the hopper is turned ON.
    When [PB1] (X20) is
    released,
    Supply command (Y0) is turned OFF. When
    Supply command (Y0) is turned ON, the hopper supplies a part.
  • When [SW1]
    (X24)
    on the operation panel is turned ON, the conveyors move forward. 
    When [SW1] (X24) is
    turned OFF, the conveyors stop.
  • After
    the sensor X10, X12
    or X14 at the left of conveyor has detected
    a part, the corresponding conveyor is set ON and carries it to the tray at the
    right end.
    The conveyor stops 3
    seconds after a part has passed the sensor
    X11,
    X13 or X15
    at the right of conveyor.
  • Large,
    medium and small parts on the conveyor are sorted by the input of sensors Upper (X0),
    Middle
    (X1)
    and Lower (X2).
·       

Lift
Control

    1)      
When
the sensor for Part on lift (X3) in the lift is turned ON, a part is carried
to either of the following conveyors according to its size.

  • Large part: Upper conveyor
  • Medium part: Medium conveyor
  • Small part: Lower conveyor

     2)      
Lift up command (Y2) and Lift down command
(Y3)
are controlled according to the lift position detected by the
following sensors.

  • Upper: X6
  • Meddle: X5
  • Lower: X4

     3)      
When a
part is transferred from the lift to the conveyor, Lift
rotation command
(Y4) is set ON. 

     4)       After
a part is transferred, the lift is to return to the initial position and stand
by.
Ladder Program Description:
In this exercise, the size of parts carried
on the conveyor is to be sorted using three sensors shown on the table.

Part size
Upper (X0)
Medium (X1)
Lower (X2)
Large
ON
ON
ON
Medium
OFF
ON
ON
Small
OFF
OFF
ON
The lift stop position is determined based
on the input status of the position sensors X4
to X6.
When distributing a small part, the lift
does not move vertically. Only the rotation of the lift 
should be controlled in
the initial position.

·        
Turn ON
[SW1] (X24) on the operation panel.
Result >>The
conveyor moves to the right.

·        
Press [PB1] (X20) on the operation panel.
Result >>A part is
supplied from the hopper.

·        
Operation
of the lift

Result >>When a
large or medium part is put on the lift, the lift moves up to the upper or
middle conveyor and stops. When a small part is put on the lift, the lift
remains in the initial position
·        
Transfer
of a part

Result >>After the
lift rotates and a part is transferred to the conveyor, the conveyor moves to
the right and the part is carried to the tray.
·        
Return
of the lift

Result >>The lift
with no part returns to the initial position and stops there.
·        
Repeated
operation

When [PB1] (X20) is pressed, the operations starting
from
2 are repeated.

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