**PLC Programming (in brief):** **PLC** stands for **Programmable Logic Controller**. It is a digital computer used in **industrial automation** to control machines, processes, or systems. ### Purpose: PLCs are used to **automate repetitive tasks**, monitor inputs, make decisions based on logic, and control outputs like motors, valves, sensors, etc. --- ### Basic Components: * **Inputs**: Sensors, switches, buttons * **Outputs**: Motors, relays, lights * **CPU**: Processes logic * **Programming Software**: Used to write the logic (typically on a PC) --- ### Common PLC Programming Languages: * **Ladder Logic (LD)** – Graphical and resembles electrical relay logic * **Function Block Diagram (FBD)** * **Structured Text (ST)** * **Instruction List (IL)** * **Sequential Function Chart (SFC)** --- ### Simple Example (Ladder Logic): **Goal**: Turn ON a motor when a start button is pressed and keep it ON until a stop button is pressed. ``` | Start | | Motor | |-------|---->|------>| | | | | | Stop |<----| | ``` ### Pseudocode Explanation: ```text If Start_Button is pressed And Stop_Button is NOT pressed Or Motor is already ON (for latching) Then Turn ON the Motor Else Turn OFF the Motor ``` This is a basic "start-stop" control logic. --- ### Real-life Applications: * Conveyor belt control * Elevator systems * Packaging machinery * Traffic lights * Water treatment plants --- If you'd like, I can show you how this logic would look in real ladder diagram software or structured text.