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Programmable Logic Controllers (PLCs): An Overview - Coggle Diagram
Programmable Logic Controllers (PLCs): An Overview
Programmable Logic Controllers
Industrial grade computer that is capable of being programmed to perform control functions
Basically a digital computer designed for use in machine control
Benefits:
Less wiring than conventional relay circuits
easy programming and installation
Relationships determined by user program instead of manner of connection
high control speed
network compatability
Parts of a PLC
CPU
Executes control logic
Processes ladder logic or other code instructions
Manages Communication
I/O
Converts real-world signals to PLC-usable signals
Power Supply
Provides DC power to PLC modules
Programming Device
Used to create and monitor PLC programs
Architecture Types
Open
Uses industry-standard components
Easier integration
Closed
Manufacturer-specific design
Limited compatibility with external devices
PLC Operation
Relay Based control solutions
Uses hardwired relay logic
Traditional motor control method
Control Logic
Pressure and temperature switches
Manual pushbutton
PLC Based Operation
Input Devices
Pressure, temperature, and push button switch
Control Logic
Software logic replaces relays
PLC vs PC
Physical Hardware
Very similar architectures
PC could be modified into a PLC easily
Operating Environment
PC needs a more conditioned environment while PLC is designed for operation in industrial environments
PC ranges for ambient temperature and humidity much more limited
Programming Method
PC uses versatrile languages like C or Python while PLC uses ladder logic
More categorized towards its execution goals
Program Execution
PLC is designed for one specific execution at a time while PC is design for multiple executions simultaneously