4. Introduction
• Fundamentally, a PLC’s job is to control a
system’s functions using the internal logic
programmed into it. Businesses around the
world use PLCs to automate their most
important processes.
• A PLC takes in inputs, whether from
automated data capture points or from
human input points such as switches or
buttons. 4
6. Working of PLC
• Based on its programming, the PLC then
decides whether or not to change the
output.
• A PLC’s outputs can control a huge variety
of equipment, including motors, solenoid
valves, lights, switchgear, safety shut-offs
and many others.
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7. Working of PLC
• The physical location of PLCs can vary widely
from one system to another. Usually,
however, PLCs are located in the general
vicinity of the systems they operate, and
they’re typically protected by a surface
mount electrical box.
• PLCs largely replaced the manual relay-
based control systems that were common in
older industrial facilities.
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8. Working of PLC
• Relay systems are complex and prone to
failure and, in the 1960s, the inventor
Richard Morley introduced the first PLCs as
an alternative. Manufacturers quickly
realized the potential of PLCs and began
integrating them into their work processes.
• Today, PLCs are still a fundamental element
of many industrial control systems.
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9. Working of PLC
• In fact, they’re still the most used industrial
control technology worldwide.
• The ability to work with PLCs is a required
skill for many different professions, from
the engineers designing the system to the
electrical technicians maintaining it.
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10. Advantages of PLCs
• PLCs are fairly intuitive to program. Their
programming languages are simple in comparison
to other industrial control systems, which makes
PLCs great for businesses that want to minimize
complexity and costs.
• PLCs are a mature technology with years of testing
and analysis backing them up. It’s easy to find
robust research about many different PLC types and
comprehensive tutorials for programming and
integrating them.
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11. Advantages of PLCs
• PLCs are available at a wide range of price
points, including many extremely affordable
basic models that small businesses and
startups often use.
• PLCs are extremely versatile, and most PLC
models are suitable for controlling a wide
variety of processes and systems.
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12. Advantages of PLCs
• PLCs are completely solid-state devices,
which means they have no moving parts.
That makes them exceptionally reliable and
more able to survive the challenging
conditions present in many industrial
facilities.
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13. Advantages of PLCs
• PLCs have relatively few components, which
makes them easier to troubleshoot and helps
reduce maintenance downtime.
• PLCs are efficient and don’t consume very
much electrical power. This helps conserve
energy and may simplify wiring
considerations.
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14. Drawbacks of PLCs
• PLCs have less capacity to handle extremely
complex data or large numbers of processes
that involve analog rather than discrete
inputs.
• As manufacturing facilities become more
integrated and involved, increasing numbers
of them may shift toward a distributed
control system or another alternative
industrial control method.
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15. Drawbacks of PLCs
• PLCs from different manufacturers often
use proprietary programming software.
• This makes PLC programming interfaces
less interoperable than they might be,
especially considering that their
programming languages share common
standards
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16. Drawbacks of PLCs
• PLCs, like many other types of electronic
equipment, are vulnerable to
electromagnetic interference (EMI).
• They can also experience other kinds of
common electronics malfunctions such as
corrupted memory and communication
failures.
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17. About PLC
• Electrical Capacity: PLCs have different
voltage requirements for their power
supplies, so check to ensure that your
selection is compatible with your electrical
system.
• Processing Speed: Check a PLC model’s CPU
speed to determine whether it meets your
application’s needs.
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18. About PLC
• Compatibility: Ensure that your PLC model is
compatible with any new or existing system
hardware, whether that’s power supplies or
DIN rails.
• Temperature Tolerance: Most PLCs are
designed for safe operation within the range
of 0 to 60°C. However, some specialized
PLC models can operate at extreme
temperatures.
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19. About PLC
• Memory: A PLC needs sufficient ROM and
RAM to execute the processes it’s intended
to automate.
• Connectivity: Make sure your PLC has
enough input and output ports, and make
sure it’s able to connect to the type of
peripherals that your system requires.
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20. About PLC
• Analog I/O: Although PLCs are primarily
used for discrete functions, some models
also have analog inputs and outputs that
can control processes with continuous
variables.
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22. Conclusion
PLC stands for Programmable Logic Controller.
They are industrial computers used to control
different electro-mechanical processes for use in
manufacturing, plants, or other automation
environments.
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