Process control and PLC tutorial - AN4603

Maxim > App Notes > A/D and D/A Conversion/Sampling Circuits Amplifier and Comparator Circuits Keywords: 4mA, 20mA, current loop, programmable logic controllers, PLC, environment monitor, personnel safety, reduce waste, improve Oct 21, 2009efficiency, factory industrial, robot communications, intermittent cable over temperature, brownout, EMI, RFI, power surge, interfereAPPLICATION NOTE 4603Process Control and PLC TutorialBy: Bill LaumeisterAbstract: Programmable logic controllers (PLC) save time, money, and energy in process control systems. They simplify systems.A brief history of manufacturing processes sets the stage for how to use modern ICs to replace discrete components. The ICsallow easy system design and extend monitoring to improve equipment and personnel safety. The MAX15500/MAX15501,MAX5661, and MAX5134–MAX5139 serve as examples of ICs in process control.IntroductionIndustrial control, factory automation, and PLC (programmable control logic)—done well, they save time, materials, energy, andmoney. But where do we begin? Building a complete automated factory is such a huge job that some might give up before starting.We are reminded of the explorer in Africa years ago who asked the native tribesman, "How does one eat an elephant?" Thetribesman looked at the famous explorer in astonishment and replied, "We eat it just like everything else, one bite at a time." Aswith most big systems, industrial control is comprised of many smaller circuits. We ...