This is PLC Program to count and pack parts from conveyor.
Problem
Description:-
Objects are moving on
conveyor 1. We need to pack five objects in the empty box. When empty box is
filled. It is carried to the storage via conveyor belt 2. Implement this
automatic cycle in PLC using ladder language.
Problem
Diagram
Problem
Solution.
Mostly inductive and
proximity sensors are used to detect objects. Here we mount proximity sensor for
the object detection and empty box detection.
Inductive sensor are
mostly used to detect metal parts and proximity sensors are used to detect
metal parts and other parts.
Here one proximity sensor is for object detection and other is for box detection. Objects are moving on conveyor 1 and boxes are moving on conveyor 2.
We will write automatic cycle for this application in PLC. So when empty box is detected on conveyor 2, conveyor 1 will be ON automatically.
And when box is filled
with five objects, conveyor belt 2 will start automatically.
Note:-Here we consider simple application for counting and
packaging application. We have taken here proximity sensor for simplicity.
Proximity sensor will sense the object and counter will count the total objects.
Program
Here
is PLC program to
count and pack parts from conveyor.
List
of inputs/outputs
Digital
Inputs
Start:-I0.0
Stop:-I0.1
Proximity:-I0.2 (part
detection)
Proximity:-I0.3 (Box
detection)
Counter reset PB:-I0.4
Digital
Inputs
Cycle ON:-Q0.0
Conveyor belt 1:- Q0.1
Conveyor belt 2:-Q0.2
M
memory
Total objects:-MW10
Relay coil: - M0.2
Ladder diagram to count and pack parts from conveyor.
Program Description
For this application we
use S7-300 PLC and TIA portal software for programming. We
can implement this logic by using other PLC also.
Network 1:- In first network we used latching circuit for cycle
ON. Here we used START PB (I0.0) to
start the cycle and STOP PB (I0.1) to stop the cycle.
Network 2:-Here when empty box is detected (I0.3) and cycle is
ON, conveyor 1 (Q0.0) will be ON.
Network 3:- Counter is used to count the objects moving on the
conveyor 1. Objects are moving on the conveyor 1 (Q0.0) and mounted proximity
sensor (I0.2) is detecting the objects. Now counter counts in the incremental
way. Total counted objects will be stored in the memory word or register
(MW10).
Network 3:- Counter is used to count the objects moving on the
conveyor 1. Objects are moving on the conveyor 1 (Q0.0) and mounted proximity
sensor (I0.2) is detecting the objects. Now counter counts in the incremental
way. Total counted objects will be stored in the memory word or register
(MW10).
Network
4:-When
five box completely packed in the box, counter output will be ON and as per
logic relay coil (M0.2) will be latched for timer operation.
Network
5:-Timer
instruction is executed when relay coil (M02.) is activated.
Network
6:-Box
is filled with five objects or counter output is ON and empty box is not
detected, conveyor belt 2(Q0.2) will be activated.
When objects are moving
on the conveyor 1, counter will count the objects. We need to pack three
objects in the box. So when box is filled with five object, timer will stop the
conveyor belt 1 and conveyor belt 2 will start automatically.
Here we have not
considered all interlocks for simplicity. Belts synchronization are assumed
because we have used timer based synchronization.
Note:-Above
application may be different from actual application. This example is only for explanation
purpose only. We can implement this logic in other PLC also. This is the simple
concept of counting and packaging application. By using this concept we can
count objects moving on the conveyor and pack it automatically.
All
parameters considered in example are for explanation purpose only, parameters
may be different in actual applications.
Runtime
Test Cases
|
Inputs |
Outputs |
Physical Elements |
|
I0.0=1 |
Q0.0=1 |
Cycle ON |
|
I0.1=1 |
Q0.0=0 |
Cycle OFF |
|
I0.3=1 |
Q0.1=1 |
Conveyor belt 1 ON |
|
I0.2=1 |
Counter increase |
MW10=1, 2, 3, 4…. |
|
"Counter".Q=1&I0.3=0 |
Q0.2=1 |
Conveyor belt 2 OFF |
|
M0.1 |
MW10=0 |
Total count zero |