The First programmable
logic controller (PLC) specified in 1968 by the Hydromantic division
of the General Motors Crop. The first
models name was invented. the Second
models came in 1970 communication abilities appears and third Model came 1980 Standardization on communication on protocols, 1990 Standardization on programming language
PLCs are
the main heart of the automation system. PLC is the controller used to control
the plant, process, system, machine. A programmable logic controller (PLC) is digital Programs use to be industrial
computer that monitor Input, makes decisions and output to controls automate
process Machine.
PLC control System :
Programmable
logic controller (PLC) in industrial digital computer control system, input or
output devices to control and easy to
make decisions, PLC controller is used
to control the plant/process/system/machine
Basic instructions :
Positive Logic
True = logic 1 = input energized.
False =
logic 0 = input NOT energized.
Negative Logic
True =
logic 0 = input NOT energized
False =
logic 1 = input energized.
Normally Open
(XIC) -
eXamine If Closed.
Normally Closed
(XIO) -
eXamine If Open
On Timer
(TON) -
Timer ON.
Off Timer
(TOF)-
Timer OFF
benefits the Programmable Logic Controller
(PLC) :
1 easily understood programming language
2 easily
to control switch (on/off)
3 easy to
operate
4 easy to
maintenance
5 high safely
6 timer and counter
