PLC COLOR SORTING MECHANISM

Objects are separated or rejected based on color.

Process is fully automated.

Mechanism is Multi-Functional, with object counter and Weight information.

Mechanism can differentiate between 3 colors: Red, Green & Blue.

User defines and controls what colors of objects are rejected through HMI.

Objects start on Conveyors.

Information is obtained through sensors and displayed on HMI.

A color sensor is placed above the conveyor.

When object passes underneath, color information is obtained.

Sensor sends the information to an Arduino Uno, acting as signal conditioning.

Main controller is a PLC, receives color signal from Arduino.

PLC takes sorting action depending on detected VS desired colors.

Sorting action is actuated through a DC motor.

Motor arm executes rotary action.

Interrupts objects, knocks them off conveyor.

A DC Motor is used that rotates both directions.

Arm attached to shaft.

Rotary motion actuates sorting.

Rotate into Conveyor to remove objects, then back.

Arm has bearing at middle, reduces object friction.

Load cell needed to be installed inside conveyor enclosure.

Holder installed connecting sides.

Fixed to one side of Load Cell, which is perpendicular to holder.

Other side is fitted with an extension to a metal “Contactor” piece that makes contact with objects.

To reduce friction with belt, Contactor piece has a semi-circular, smoothly finished surface.

Slight Bump helps with sensing objects.

Such setup exerts tension + compression forces on LC, resulting in more accurate readings.

Placed foam risers to prevent conveyor interfering with readings.

Main controller is a Siemens S7-1200 PLC.

Programmed Using Ladder Logic + Some Function Blocks in TIA Portal V16.

SR Flip-Flop

Start/Stop Buttons

Master Switch Memory Bit

Controls other functions

Counter

HMI connected through Profinet.

Displays information.

Collects user input.

oObject Count + Weight.

oControl for color rejection.oVariables Manipulated in PLC.

Modbus TCP

TCP/IP Connection

Parameters

Mode

Data Address

Length

PTR Data Buffer

Sorting condition = Modbus register bit + HMI Switch

Confirmation bit 2 actions

Executes Function + increments counter

Any Execution action starts the sorting sequence.

Motor moves for X seconds in + Direction, pause, X seconds in – Direction.

Solved with 4 Timer functions (T1,T2,T3,T4) , 2 SR Flip-Flops.

Timer equations:
TF = T2 - T1

TP = T3 - T2
TR = T4 – T3
T1 & T2 control forward movement, T3 & T4 control backward movement.

Bit Reset operations.

Ensures return to ready status after execution.