Overhead Crane Control of Degreasing Operation

Block Diagram:

Working:

Basic Working:

In this application, the product needs to be degreased in the degreasing tank

before being passed in the next section.

When the Start button (A) is pressed the roller(motor) will coil up the hook until

up position (S3).The hook will then move left until it reaches the S4 position.

It will then stop and lower the product into the degreasing tank.When it reaches

down to S2 position, the product will stay in degeasing tank for 10 seconds.After

the time is up, the product is lifted up and moved left until it reaches S5 position

and stop.It continues to come down until the down position S2, where the buzzer

will sound. The operator will collect the product and press the Reset button (B) to

return the crane back to starting position.

Explanation:

The stepper motor 1 with input y1 and direction input y0 is used to lift

the crane hook upward and downward. The stepper motor 2 with input

y3 and direction input y2 is used for moving crane hook left and right.

The clockwise rotation of motor 1 moves the hook upwards and

anticlockwise rotation of motor 1 moves the hook downward .The

clockwise rotation of motor 2 moves the hook towards right and

anticlockwise rotation of motor 2 moves the hook towards left.

N000,N001,N002: Registers R1,R2,R3,R4,R5,R6,R7,R8,R9 are initialized

with value 0.

N005:Register R1 is compared with 0 and if R1=0 M9 coil is energized

which allows the x1 button to be used for starting the operation of

crane.

N008: x1 button is used to start motor 1 to move the hook upward.20

rotations are required to moves the hook to the position up(S3)

therefore the PLSO function generates 960 pulses at the rate of 96

pulses per second.

N011:The hook is moved left from position S1 to S4.Total 30 rotations

are required to reach S4 position.So 1440 anticlockwise pulses are

generated by PLSO function for motor 2.

N013:The hook is moved downward from position S3 to S2 by

generating 960 anticlockwise pulses for motor 1.

N017:Timer T0 generates a delay of 10sec so the product carried by

hook remains in degreasing tank for 10 seconds.

N022: The hook is moved upward from position S2 to S3 by generating

960 clockwise pulses.

N023:The hook is moved left form position S4 to S5 by generating 1440

anticlockwise pulses for motor2.

N026:When the hook reaches position S5 its moved downward to

position S2.

N028:A buzzer is sound for 5 sec when the hook reaches destination

position S2.

N033:The button X2 is used to reset the hook so it reaches the starting

position S2.The button X2 can only be used to move the hook to

starting position if the hook has reached the position S5 or the position

of the receiving operator.Therefore 960 clockwise pulses are generated

to move the hook upward.

N037:Total 60 rotations are required to move the hook from position

S5 to S1. Therefore 2880 clockwise pulses are generation for motor 2.

N040:The hook is moved from up S3 position to down position S2

which is the starting position of hook.

N043:All the registers are initialized with 0 so the whole process can be

started again by pressing x1 button.

Calculations:

20 rotations=(20)X(48)=960 pulses

30 rotations=(30)X(48)=1140 pulses

60 rotations=(60)X(48)=2880 pulses

LADDER DIAGRAM: