PLC Conveyor Sorting System (Siemens LOGO!)

A simple PLC automation project that sorts workpieces on a conveyor using a metal sensor and a simulated SCARA robot pick-and-place operation.

Main features

• Conveyor start/stop control
• Emergency stop safety
• Workpiece detection
• Metal vs plastic classification
• Robot pick-and-place sequence
• Timer-based delays

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System Overview

1. Start Button starts the conveyor motor.

2. Workpiece Sensor detects an object on the conveyor.

3. Metal Sensor determines if the object is metal.

4. The correct sorting output is activated:

   • Metal → Metal Sorter
   • Non-metal → Plastic Sorter

5. If the robot is ready, it performs a pick operation.

6. After a delay, the robot performs a place operation.

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Ladder Logic

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Inputs

Input	Name	Function
I1	Start_Button	Starts the conveyor
I2	Stop_Button	Stops the conveyor
I3	Workpiece_Sensor	Detects objects
I4	Metal_Sensor	Detects metal
I5	Robot_Ready	Robot ready signal
I6	Emergency_Stop	Stops the system immediately

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Outputs

Output	Name	Function
Q1	Conveyor_Motor	Drives the conveyor
Q2	Plastic_Sorter	Sorts plastic objects
Q3	Metal_Sorter	Sorts metal objects
Q4	Robot_Pick	Robot picks the object
Q5	Robot_Place	Robot places the object

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Timers

Timer	Name	Function
B007	Pick_Delay	Delay before robot pick
B008	Place_Delay	Delay before robot place

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Function Block Diagram (FBD)

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Software

• Siemens LOGO! Soft Comfort
• PLC Simulation
• Ladder Logic (LAD)
• Function Block Diagram (FBD)

Author

Marai Abed Alrahman
Budapest University of Technology and Economics (BME)