What is PLC ? Programmable Logic Controller
now we discus about programmable logic controller
what is plc
A digital electronic device that uses a programmable memory to store instructions,. and to
implement specific functions such as logic, sequence, timing, counting and arithmetic operations to
control machines and processes
the block diagram of plc
a PLC has three basic sections namely
Input Output section
Processor section
Proagram loader section
The input section converts the field signals to logic-level signals that the PLCs processor can read directly.
The process section reads these inputs, processes the signals executing the program, and prepares the
output signals.
The output section converts the logic level output signals coming from the processor section into high level
signals and realease signals for various field devices.
The program loader is used to enter the users program into, to memory or change it and to monitor the
execution of the program.
different types PLC manufacturers
Allen Bradley
Siemens
GE Fanuc
ABB automation
Schneider Electric
Omron
delta