Tuesday, January 24, 2017

IAM Search

Programmable Logic Controllers

Electromechanical relays are versatile and reliable devices, and it is possible to perform virtually any control function given enough relays and wiring. However, they are subject to wear due to their moving parts, and re-configuring a relay-based control system entails disconnecting and re-connecting wires: a tedious task at best. Solid-state logic gates may replace electromechanical relays to avoid problems of wear (as well as vastly increase speed of response), but once again re-configuration would require disconnecting and re-connecting many wires between the gates.

A very practical alternative to relay- or gate-based control logic circuits is to use a programmable computer to perform the same functions. A computer equipped with the necessary input and output peripheral circuits, configured to be easily programmed by technical personnel for virtually any logical task, is called a programmable logic controller or PLC.

Click the subtopics below to read more about Programmable Logic Controllers


References

“1758 PLC-5 Programmable Controllers Addressing Reference Manual”, Publication 5000-6.4.4, Allen-Bradley Company, Inc., Milwaukee, WI, 1995.

“Allen-Bradley I/O Modules Wiring Diagrams”, Publication CIG-WD001A-EN-P, Rockwell Automation, Inc., Milwaukee, WI, 2005. IEC 61131-3,

“International Standard, Programmable Controllers – Part 3: Programming Languages”, Edition 2.0, International Electrotechnical Commission, Geneva, Switzerland, 2003.

“Logix5000 Controllers I/O and Tag Data”, Publication 1756-PM004B-EN-P, Rockwell Automation, Inc., Milwaukee, WI, 2008.

“Programming with STEP 7”, Siemens AG, N¨urnberg, Germany, 2006.

“S7-200 Programmable Controller System Manual”, Order Number 6ES7298-8FA24-8BH0, Edition 09/2007, Siemens AG, N¨urnberg, Germany, 2007.

“SLC 500 Family of Programmable Controllers Addressing Reference Manual”, Publication 5000- 6.4.23, Allen-Bradley Company, Inc., Milwaukee, WI, 1995.

“SLC 500 Modular Hardware Style User Manual”, Publication 1747-UM011E-EN-P, Rockwell Automation, Inc., Milwaukee, WI, 2004.

Go Back to Lessons in Instrumentation Table of Contents


Comments (0)Add Comment

Write comment

security code
Write the displayed characters


busy

Related Articles

Promotions

  • ...more

Disclaimer

Important: All images are copyrighted to their respective owners. All content cited is derived from their respective sources.

Contact us for information and your inquiries. IAMechatronics is open to link exchanges.

IAMechatronics Login