PLC is discussed in detail in simple language.
The light of
technology is spreading all over the world. Technology has developed very
rapidly in recent years.
Technology has reached almost all fields starting from
agriculture. Similarly, the touch of technology has had a huge impact on the
industry.
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Most of the
mining industries use automation equipment which results in much better work
efficiency and also reduces the production cost of the product.
PLC is a very important subject for students who study electronics. Because there are job
opportunities in the industry with PLC even though it is very limited.
Besides,
anyone can learn PLC. If you want to build your career on PLC, you need to know
the intricacies of PLC very well.
In the
industry, automation is the first name of two devices,
1.
Microcontroller
2. PLC.
What are PLC and something about PLC
PLC Full Name
Programmable Logic Controller. It is a device that can be used to easily
control other devices.
It is a type of an industrial computer control system that will make a decision as soon as it
receives any signal at the input depending on the custom program and will
control the output.
PLC usually
consists of a microprocessor that has to be programmed with the help of a
computer.
he program is basically written in computer software and loaded into
the PLC with the help of a cable. We will discuss this in detail below.
Why PLC has used more than a microcontroller?
PLC is much more expensive
than microcontrollers, which is why PLC is still used more.
The input-output capacity of PLC is much higher than that of microcontrollers.
Input and output can be increased by adding additional or external modules in
PLC.
Compared
to microcontrollers, PLCs may have single processors and CPUs that are not
typically present in microcontrollers.
The
processing capacity of PLC is much higher and faster than that of
microcontrollers.
If
any PLC device is damaged, it can be quickly replaced.
It
is much easier to program in PLC.
The microcontroller has no display unit whereas the PLC has a display unit.
Work
can be monitored with the help of PLC's display unit; The microcontroller does
not have a display unit but can be fitted separately if required.
PLC the operation cannot be affected by temperature changes, dust, humidity, etc.
whereas microcontrollers have a lot of influence on these issues.
PLC
can work with high voltage were working at high voltage in microcontrollers is
a lot of trouble.
Another important difference is that the program needs to be written for the microcontroller
later but the work can be done quickly and very easily through the ladder
diagram in PLC. PLC Bangla Tutorial will discuss PLC in full detail.
Where is PLC used?
We know that
PLC is a digital computer that is used to control the necessary equipment in
different factories.
Used in any
machine automation, nuclear power generation plant, chemical industry,
automated industry, home automation, etc.
PLC is familiar with popular brands
Currently PLCs
of various companies are in the market. However, the list of some of these
well-known PLCs is given below.
·
Delta
plc
·
Ellen
Bradley
·
Mitsubishi
·
Fuji
·
Hitachi
·
L.G.
·
Medicon
·
Toshiba
·
Siemens
The most
popular of these is "Siemens". I have personally seen Siemens work
with most places.
A detailed discussion of PLC pin diagram
No matter what
PLC and microcontrollers talk about, they all have input and output pins. There
will also be a power supply part to activate the device.
Different parts
of Siemens, plc have been identified in the figure above. The power supply of
this PLC should be between 115 to 240 volts in AC or DC. Need to connect phase
or positive with L1 and neutral with N.
There are a
total of eight digital input pins from I1 to I8. Limit switches,
photodetectors, push switches, timers, circuit breakers, etc. are used as these
inputs.
Also, I7 and I8 pins can be used as universal input.
This module has
four output pins. Output ranges from Q1 to Q4. The output pins basically act
like a switch. They are open and closed in different conditions.
Q is the output
pin of the PLC. The PLC has to be connected to the load as shown in this
figure. Name of output device: motor, light, alarm, valve, control relay, etc.
PLC has a
monitor with which the work can be monitored.
There are some
buttons next to the PLC through which various commands can be given.
If the ladder
logic or program is too large, it can be loaded on the SD card.
The biggest
advantage of PLC is that it can add external modules. This can increase the
input-output which is shown in the figure below.
How does PLC work?
PLC is a type
of a microcontroller-based control system. It has a programmable memory that
stores various types of instructions.
Through this arithmetic (mathematical)
logical, sequencing, timing, etc. functions are performed.
Depending on
the PLC function, the input signal that will be given in the first step will be
processed through the ladder diagram and the desired output signal will be
obtained in the second step. This allows other devices to be easily controlled.
PLC has three
main sections:
- Power supply
- Input / output
- Central Processing Unit
Power supply
It must take a
power to activate PLC. The function of the power supply is to supply the
required power to the input, CPU, and output.
One more thing, it must have to earth. If earthing is not done, the program may not run properly and may
even be deleted.
In the case of
different PLCs, the required power may be more or less. There are many PLCs
that require 115 volts to 240 volts AC / DC to operate. Again, there are many
PLCs that can only be operated at DC 24 volts.
Input /
output
Input
Different types
of information are provided here. The information received on the input device
is sent to different parts of the output device according to the ladder
diagram.
Input usually
sends various types of switches, sensors, temperature information, variable
voltage, etc. information to the central processing unit.
The output CPU
will be discussed later for ease of understanding.
Central Processing Unit
The information
coming from the input is sent to different parts of the output device according
to the ladder diagram.
In addition, the data received from the input device may
be connected to some of its own data according to the CPU diagram.
Output
The information
from the central processing is sent to the machine through the relay switch and
the machine works accordingly.
The machine
re-input information through other devices, including sensors, and thus the cycle continues automatically.
Well, let's take a look at the whole process
First, you have
to activate the PLC with the required power. Switches, sensors, etc. are used
as inputs of PLC. If we get a signal at the sensor or switch input, that
information will go to the CPU.
The CPU will control the output (motor, lamp,
etc.) according to the ladder diagram.
Things to know in case of PLC program
Let's start
with an example:
If your dad
tells you to come up with this month's electricity bill before the 10th, you
will pay the electricity bill before the 10th.
Again, if you are asked to pay
the electricity bill on the 12th, then you will pay the electricity bill on the
12th.
This means that
you are doing the work after giving an instruction. In the same way, you have
to explain to the PLC what work you want to do with him.
We already know
some general things about PLC. Now we will know how to load the program in PLC
and some methods.
- PLC programming software
- PLC CPU
- Computer
- Communication cable
PLC programming software
First, you would
like to make certain which brand of PLC you'll use. then you've got to put in
PLC software on PC consistent with that brand.
If you're employed with Siemens
PLC, you'll download and install Logo software.
However, is one of the foremost used and popular software within the
software industry.
However, it's better to start out with the brand software to
find out the fundamentals. the way to install the software is going to be
discussed within the next article.
PLC CPU
In PLC CPU
you'll increase the external input-output if you would like.
Suppose you'll
use 36 inputs and 24 outputs but you'll need more inputs and outputs, then
you'll add external modules and it's very easy.
But within the
case of all PLCs, you cannot do input and output extensions if you would like
to. Only modular PLC extensions are possible. I.e. one compact PLC and
therefore the other modular PLC.
Computer
Most computer
users today use the newest Windows 8. However, Siemens' logo software runs
alright in Windows 10, starting with Windows XP.
Logo software is often used
for Windows OS, Ubuntu OS, Mac OS.
Communication cable
Because there
are different cables available within the market which don't work properly.
Therefore PLC communication cable PLC should be taken from the corporate of
that company. Although the worth of cable is far higher.
In the first episode of PLC Bangla Tutorial, I will be able to attempt to write more details
about PLC Bangla Tutorial within the future.
Until then, everyone is going to
be fine and healthy. we would like to listen to you. If there's any good
or bad, any suggestion, etc., comment and if you wish it, share it.