Problem Description

Runtime Test Cases
Inputs
Output Physical Elements
I:1/0 = 1 (Start PB) O:2/1 = 1 Run conveyor motor
I:1/3 = 1
B3:0/0 = 1
Set first bit of bit register
I:1/2 = 1
BSL = 1 Shift bit to left
B3:0/3 = 1
O:2/2 = 1 Activate blower
PLC Program to Perform Capping of Beverage Bottles
This is a PLC Program to Perform Capping of Beverage Bottles.
Problem Description
Beverage bottles are moving on a conveyor belt. Capping of these bottles is performed. Crown cork caps
are used for these bottles. Implement automation of this process in PLC using Ladder Diagram
programming language.
Problem Diagram
Problem Solution

To sense the bottle, proximity sensor is used.

Timer is used to stop the conveyor for 1sec for capping procedure.

Bit Shift register is also used to perform this operation.

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
Count the number of steps capping machine is placed from the sensor and set bit position to operate
capping machine accordingly.

In this example as you can see, bottle is 8 steps away from the proximity switch, so if Bit register B3:0 is
used, then capping machine should be operated when B3:0/0 is shifted to B3:0/7.

Capping machine is operated by pneumatic system. It is activated by air supply when energized.

Similarly we can even make an arrangement where two capping machines are operated, one to cap small
bottles and other for larger bottles.
PLC Program
Here is PLC program to Perform Capping of Beverage Bottles, along with program explanation and run
time test cases.
List of Inputs and Outputs
I:1/0
= Start
(Input)
I:1/1
= Stop
(Input)
I:1/2
= Proximity
(Input)
O:2/0
= Master coil / Run
(Output)
O:2/1
= Conveyor motor
(Output)
O:2/2
= Capping machine
(Output)
BSL
= Bit shift left instruction
(Logical)
B3:0
= Bit shift Register
(Register)
B3:0/7 = Bit to energize capping machine
(Bit)
R6:0
= Control register
(Register)
T4:0
= Timer to stop conveyor for capping
(Timer)
LIM
= Limit output to perform capping before conveyor starts again
(Compare)

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