The main functions of a PLC (Programmable Logic Controller) are to monitor inputs, process logic, and control outputs in an automated system. A PLC continuously receives signals from sensors, switches, and other devices, checks them against the program logic, and sends control commands to motors, relays, valves, or lights. This helps machines run automatically without manual control.
In simple terms, the key functions of a PLC include:
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Input scanning – Reading the current status of all connected input devices.
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Program execution – Processing the logic or instructions written by the user.
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Output control – Activating or deactivating output devices based on logic results.
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Diagnostics and communication – Monitoring system health, detecting faults, and communicating with HMIs or other controllers.
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Data handling and storage – Storing values, counters, and timers for process tracking.
All these functions work together in a continuous loop called the scan cycle, allowing the PLC to control industrial machines quickly, safely, and efficiently.