Industrial Conveyor Belt Automation with OpenPLC

A professional, industry-standard automated control system designed in OpenPLC Editor v4 using IEC 61131-3 Ladder Diagram (LD) logic. This project demonstrates core industrial automation concepts: latching circuits, safety interlocking, signal filtering via timers, and live status feedback indicators.

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Skills Demonstrated

• IEC 61131-3 Ladder Diagram programming
• Industrial control system design
• Safety interlocking and emergency stop logic
• Signal conditioning and noise filtering
• Digital I/O mapping and memory allocation
• Technical documentation and system specification

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System Specification & Process Flow

1. System Start: Pressing the green Start Button (Start_PB) seals in power to activate the main Conveyor motor.
2. Visual Warning: When the conveyor starts moving, a virtual Running_Lamp pilot light immediately illuminates to alert floor operators.
3. Arrival Detection: When a box lands on Sensor_1 at the beginning of the belt, an internal On-Delay Timer (Timer_1) filters the signal for 2 seconds to prevent false triggers from dust or vibrations.
4. End-of-Line Stop: Once the box reaches the end of the line and trips Sensor_2, the latching circuit breaks instantly, turning off both the motor and the indicator light safely.
5. Emergency Manual Cutoff: Pressing the red Stop Button (Stop_PB) interrupts power at any stage to stop all operations instantly.

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I/O Memory Assignment Table

Variable Name	Electrical Device	PLC Address	Type	Memory Description
Start_PB	Push Button (NO)	%IX0.0	BOOL	Physical System Start Input
Stop_PB	Push Button (NC)	%IX0.1	BOOL	Physical System Emergency Stop
Sensor_1	Proximity Sensor	%IX0.2	BOOL	Arrival Detection Sensor
Sensor_2	Proximity Sensor	%IX0.3	BOOL	Destination Detection Sensor
Conveyor	Electric Motor Drive	%QX0.0	BOOL	Main Actuator Output
Running_Lamp	Pilot Indicator Light	%QX0.1	BOOL	Visual Operational Status Feedback
Timer_1	On-Delay Block	Internal	TON	Local 2-Second Safety Timer Logic

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Ladder Logic Workspace Architecture

Rung 0: Latching & Safety Cutoff Interlocks

Creates a "seal-in" circuit utilizing a parallel contact from the Conveyor output, passing through negated safety barriers (Stop_PB and Sensor_2) in series to prevent accidental resets.

Rung 1: Signal Conditioning Safety Timer

Inputs the raw Sensor_1 bit into a 2-second standard On-Delay (TON) block, buffering input changes against brief sensor flickers.

Rung 2: Auxiliary Status Feedback Loop

Monitors the state of the Conveyor output bit to cleanly switch the high-voltage operational warning pilot lamp (Running_Lamp).

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Live Simulation Screen Samples

Below are the workspace captures showing the completed variable table and live logic paths inside OpenPLC Editor: