Training
Training
Training
By :
P.L.C.
(PROGRAMMING LOGIC CONTROLLER)
WHAT IS P.L.C ??
Automation of many different processes, such as controlling machines,
basic relay control, motion control, process control is done through the use
of small computers called a programmable logic controller (PLC).
This is actually a control device that consists of a programmable
microprocessor, and is programmed using a specialized computer
language.
A modern programmable logic controller is usually programmed in any one
of several languages, ranging from ladder logic to Basic or C. Typically, the
program is written in a development environment on a personal computer
(PC), and then is downloaded onto the programmable logic controller
directly through a cable connection.
Programmable logic controllers contain a variable number of Input/Output
(I/O) ports
The programmable logic controller circuitry monitors the status of multiple
sensor inputs, which control output.
BLOCK DIAGRAM OF P.L.C
P . L . C.
PLC MANUFACTURERS
SIEMENS
ALLEN BRADLEY
SCHENIDER
MITSUBISHI
ABB
GENERAL ELECTRICS
TYPES OF PLC OUTPUTS
1. RELAY TYPE
2. TRANSISTOR TYPE
3. HIGH SPEED OUTPUT
4. TRIAC TYPE
PROGRAMMING
TYPES OF INPUTS/
OUTPUTS
1. USER TYPE: These are the inputs and outputs
that are physically present and are practically to
the inputs and outputs of the PLC.
I/P O/P
0 0
1 1
XIO ( Examine if open)
I/P O/P
0 1
1 0
LADDER LOGIC
Ladder logic is mainly used for PLC
programming.
Ladder logic programming is different
from other methods of programming.
In this we have to mage logics as per
the requirements & have to implement
them.
In ladder logic at the left hand side
there is input and at the right habd side
there is output and in between the
control components are used.
SIMPLE LADDER LOGIC
STARTING WITH RSLOGIX5000
TIMERS
Timers are used to perform the timing
operations.
Time base is the minimum value of
time in second that can be taken by
the timer.
Preset value is the total number of the
seconds for which the timing operation
has to be done
Accumulator starts increasing the time
in seconds upto the preset value.
Upto the preset value of the
accumulator the enable bit of timer is
high & the timer runs.
When accumulator reaches the preset
value then the timer stops and the
done bit of the timer becomes high
TIMER BITS
EN- Enable- This bit will high when the
input is given to the timer