PLC
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(Programmable Logic Controller)
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What is a Programmable Logic Controller (PLC)?
Many years before the PLC was invented, machine controllers used combinational circuits, like
a combination of many relays, timers or any other
devices, mechanical controller like cam shafts and drums, including electronic circuits to
make a sequence process (logic control system). With
this old sequential controller, the circuit looks very crowded and usually it's hard to find the malfunctioning part, or
to even modify the sequence, also requires more time and cost. The old sequential controller
was
implemented only in small scale or medium scale systems and was specific to a
system or machine. Because in large scale systems, it is hard to test the
ability and the efficiency of the entire system. This system also cannot be implemented in the process that needs a high speed control. So
that's why the
PLC was invented. Many new industries have already implemented PLC
systems to control their machines.
PLC is operated by the instruction input from the input devices (like push
button switch, selector switch, digital switch, etc. provided on the operation
panel, or sensors input from the limit switch, proximity switch, etc.) used to
detect the operation condition of the equipment, and serve to control the
driving loads, output devices (such as solenoid valve, motor, electromagnetic
clutch, etc. and indication loads such as pilot lamp, digital indicator,
etc.). The transmission of output signal against these input signals is
determined by the contents of PLC program to be provided to the PLC. The light
loads such as small type solenoid valve, pilot valve, pilot lamp, etc. can be
directly driven by the PLC, however, the heavy loads such as 3-phase motor,
large capacity solenoid valve, etc. need to be driven through the contactor or
the intermediate relay. Such contactor, intermediate relay, power breaker,
etc. are installed in the control panel together with the PLC. The PLC will
play an important role as a small type, high-reliability and flexible brain
when designing the automated product machining, assembling, transfer,
inspection, packing, etc.
The PLC is composed of electronic circuits with a micro-computer
(micro-controller) centered, however, it can be equivalently regarded as an
integrated body of ordinary relay, timer, counter, etc. The input relay built
in the PLC is driven by the external switch through the input terminal. The
output relay built in the PLC is provided with various internal contacts in
addition to the external output contact. Besides, it is incorporated with
various types of elements such as timer, counter, auxiliary relay, state, coil
and function block, etc. In addition, these elements are provided with many
electrically normally-open contacts and normally-close contacts, and can be
used optionally within the PLC.
Joliet Technologies and
PAN-TECH Engineering, Inc...
Pan-Tech was created in 1990 as a part time business for building
electrical panels. In 1995 the company expanded into engineering, process
control, programming, PLC programming, and machine building and is also currently involved in
process integration and data collection.
Pan-Tech is staffed with talented individuals
specializing in manufacturing
and process control in the pharmaceutical, food, chemical, and health care
industries.
One of the company's main focuses is personalized service to customers.
Working with plant personnel from the visionaries, to the supporters, to the
users. Pan-Tech strives to develop workable solutions to best fit the
environment. They then provide continuous support for these solutions.
Pan-Tech benefits from its relationship with Indicom by providing highly
organized and efficient turnkey solutions to any electrical application. As
the company continues to grow, its plans include expanding into software
validation and home automation.
PAN-TECH Engineering is
dedicated to provide the highest quality equipment and service. With our
experience, expertise and commitment, you will be completely satisfied with
our workmanship and our work ethic.
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