Programmable logic controller
Power supply
CPU (Central Processing Unit)
Input/Output section
A specialised device for controlling machines and processes
there are many shapes and sizes: some are pocket-sized while others need large racks to hold their various parts
Provide electricity in either AC or DC form
Consists of a microprocessor, memory chip and other integrated circuits to control logic, monitoring and communications
Programming mode
run mode
It downloads a program from an external PC
It executes the program and operates the process
It is used in many industries from factory to oil refineries
Provides the physical connection between the external components and the PLC
Input
Output
Give a signal that is either on or off
digital
Turns a device on or off
Analogue
Converts the digital output from CPU in voltage or current