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PROGRAMMABLE LOGIC COMPUTERS - Coggle Diagram
PROGRAMMABLE LOGIC COMPUTERS
1. What is a PLC?
Definition: A digital computer built to control machines and processes in factories and industries.
Why it is useful: * It is easy to program and install.
It replaced old, complicated physical wires (hardwiring) and relay control circuits.
Main Advantages:
Small and inexpensive (cheap).
Fast control speed.
Highly reliable (safe and dependable).
Strong against vibrations and physical impacts.
2. Main Functions
Because its structure is like a regular computer, a PLC can do tasks such as:
Timing and Counting.
Calculating (math).
Comparing information.
Processing analogue signals (handling continuously changing physical data).
3. Core Parts of a PLC
A typical PLC system needs four basic parts to work:
The Central Processing Unit (CPU): The brain that processes information.
The Input/Output (I/O) Section: Connects the PLC to real-world machines.
The Power Supply: Gives electrical power to the system.
The Programming Device: The tool used to write and load the instructions.
Memory Type: Control programs are safely stored inside battery-packed or non-volatile memory (so they are not lost when power goes out).
4. Types of System Design
Open Architecture: An open design that allows devices and programs from different manufacturers to connect easily.
Closed Architecture: A closed design that is proprietary; it cannot easily connect to other systems.
3. Core Parts of a PLC
A typical PLC system needs four basic parts to work:
The Central Processing Unit (CPU): The brain that processes information.
The Input/Output (I/O) Section: Connects the PLC to real-world machines.
The Power Supply: Gives electrical power to the system.
The Programming Device: The tool used to write and load the instructions.
Memory Type: Control programs are safely stored inside battery-packed or non-volatile memory (so they are not lost when power goes out).
5. Types of Hardware Structure (I/O Types)
Fixed I/O: Common in small PLCs. Everything is built into one single box with no separate or removable parts. It is cheaper but less flexible.
Modular I/O: The system is divided into separate parts (modules) that you plug into a frame called a rack.
How it works: When a module slides into the rack, it connects to a main circuit board called the backplane. This allows the CPU to talk to all the modules instantly.
Advantage: Highly flexible because you can change or add parts easily.