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Basics of PLC Programming - Coggle Diagram
Basics of PLC Programming
Standard PLC Languages
Ladder Logic (LD)
Graphical language using ladder diagrams
Function Block Diagram (FBD)
Graphical language using interconnected function blocks
Sequential Function Chart (SFC)
Graphical language using flowcharts
Structured Text (ST)
High-level text-based language
Instruction List (IL)
Text-based language using instruction lists
Memory Map of PLC Processor
Program Memory
Stores user-written program
Data Memory
Software-Based Logic Simulations
System Memory
Contains operating system and firmware
Configuration Memory
Stores hardware configuration and settings
PLC Program vs. Data Files
PLC Program
Defines logic and control flow
Data Files
Data File Organization
PLC Scan Cycle
Input Scan
Output Scan
Housekeeping
Program Execution
Input Branch Instructions
Used to branch logic based on input status
Instruction Address
Location in memory where data is stored
PLC Modes of Operation
Test Mode
Run Mode
Program Mode
Ladder Logic Symbols
Examine If Open (XIO) Instruction
Examines if input is open (inactive)
Logically true When input is open (inactive)
False State When input is closed (active)
Status bit 0 if input is closed (active)
Status bit 1 if input is open (inactive)
NO Contact
NC Contact
Coil
Examine If Closed (XIC) Instruction
Examines if input is closed (active)
False State When input is open (inactive)
Logically true When input is closed (active)
Status bit 1 if input is closed (active)
Status bit 0 if input is open (inactive)
Ladder Logic Rung