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Maxim > Design Support > Technical Documents > Application Notes > A/D and D/A Conversion/Sampling Circuits > APP 4490
Maxim > Design Support > Technical Documents > Application Notes > Amplifier and Comparator Circuits > APP 4490
Maxim > Design Support > Technical Documents > Application Notes > Analog Switches and Multiplexers > APP 4490
Keywords: programmable logic control, PLC, automation, closed loop control, process machine, ADC,
DAC, A/D, D/A, parameter, switch, signal chain
APPLICATION NOTE 4490
How Signal Chains and PLCs Impact Our Lives
By: Bill Laumeister, Strategic Applications Engineer
Mar 29, 2012
Abstract: It is incredible how many programmable logic controls (PLCs) around us make our modern life
possible and pleasant. Machines in our homes heat and cool our air and water, as well as preserve and
cook our food. This tutorial explains the importance of PLCs, and describes how to choose component
parts using the parametric tools on the Maxim's website.
A similar version of this article was published February 29, 2012 in John Day's Automotive Electronic
News.
Introduction
Automation by closed-loop signal-chain control is everywhere. It makes our homes more pleasant. It gives
automobiles the ever-widening range of functions that goes beyond the freedom to travel. It is, in fact,
quite astounding to look around and realize that so many of the today's products are manufactured with
the help a closed-loop signal chain. It is also important to note that in industrial plants and factories, a
more complex form of a signal chain is called a programmable logic controller (PLC). In this tutorial, we
will see that signal-chain and PLC applications are limited only by our imaginations.
Signal Chains All Around You
Signal chains surround us. They make our modern life possible and pleasant. In fact, an application with a
signal chain appears anytime one needs a control loop to monitor, manage, handle, regulate, limit, or
organize something.
Machines using signal chains heat and cool air and water in our homes. They chill and cook our food. In
industry almost everything that we buy is manufactured utilizing signal chains. Think of your automobile.
(Yes, most of us jump into our cars without thinking. We drive our automobiles to work and some people
drive using the "bang-bang" approach. This is not the bang-bang servo that we discuss in the Appendix,
but actually hitting things.) Automotive antilock brakes, cruise controls, automatic transmissions, and
traction controls are examples of signal-chain uses.
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