imported>Kvng: review: link scope. add link. no need to single out Windows. rm unnec and inaccessible cite (many other live sources are available if we think we need multiple here). disconnection is not only mitigation suggested.

2025-12-31T01:28:16Z

review: link scope. add link. no need to single out Windows. rm unnec and inaccessible cite (many other live sources are available if we think we need multiple here). disconnection is not only mitigation suggested.

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imported>Grayfell: Undid revision 1307638403 by Buuzbashi (talk) Not a reliable source. Please do not add spam

2025-11-20T07:40:22Z

Undid revision 1307638403 by Buuzbashi (talk) Not a reliable source. Please do not add spam

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imported>Kvng: review: ce for clarity. rm rep, unsourced.

2025-06-14T21:23:35Z

review: ce for clarity. rm rep, unsourced.

← Previous revision		Revision as of 21:23, 14 June 2025
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	In 1968, GM Hydramatic,<!--Don't link hydramatic transmission--> the [[automatic transmission]] division of [[General Motors]], issued a [[request for proposal]]s for an electronic replacement for hard-wired relay systems based on a white paper written by engineer Edward R. Clark. The winning proposal came from Bedford Associates from [[Bedford, Massachusetts]]. The result, built in 1969, was the first PLC and designated the ''084'', because it was Bedford Associates' eighty-fourth project.<ref name=":9">{{Harvnb\|Laughton\|Warne\|2002\|loc=chpt. 16}}</ref><ref name=":0">{{Cite web \|url=https://www.automationmag.com/855-the-father-of-invention-dick-morley-looks-back-on-the-40th-anniversary-of-the-plc/ \|title=The Father of Invention: Dick Morley Looks Back on the 40th Anniversary of the PLC \|last=Dunn \|first=Alison \|date=2009-06-12 \|website=Manufacturing Automation \|access-date=2020-02-23 }}</ref>		In 1968, GM Hydramatic,<!--Don't link hydramatic transmission--> the [[automatic transmission]] division of [[General Motors]], issued a [[request for proposal]]s for an electronic replacement for hard-wired relay systems based on a white paper written by engineer Edward R. Clark. The winning proposal came from Bedford Associates from [[Bedford, Massachusetts]]. The result, built in 1969, was the first PLC and designated the ''084'', because it was Bedford Associates' eighty-fourth project.<ref name=":9">{{Harvnb\|Laughton\|Warne\|2002\|loc=chpt. 16}}</ref><ref name=":0">{{Cite web \|url=https://www.automationmag.com/855-the-father-of-invention-dick-morley-looks-back-on-the-40th-anniversary-of-the-plc/ \|title=The Father of Invention: Dick Morley Looks Back on the 40th Anniversary of the PLC \|last=Dunn \|first=Alison \|date=2009-06-12 \|website=Manufacturing Automation \|access-date=2020-02-23 }}</ref>

	Bedford Associates started a company dedicated to developing, manufacturing, selling, and servicing this new product, which they named '''{{visible anchor\|Modicon}}''' (standing for modular digital controller). One of the people who worked on that project was [[Dick Morley]], who is considered to be the father of the PLC.<ref name=":1">{{Cite web\|url=https://www.isa.org/standards-and-publications/isa-publications/intech-magazine/2003/august/cover-story-50th-anniversary-leaders-of-the-pack/\|title=Leaders of the pack\|last=Strothman\|first=Jim\|date=2003-08-01\|website=ISA\|url-status=live\|archive-url=https://web.archive.org/web/20170808184918/https://www.isa.org/standards-and-publications/isa-publications/intech-magazine/2003/august/cover-story-50th-anniversary-leaders-of-the-pack/\|archive-date=2017-08-08\|access-date=2020-02-24}}</ref> The Modicon brand was sold in 1977 to [[Gould Electronics]] and later to [[Schneider Electric]], its current owner.<ref name=":0" /> About this same time, Modicon created [[Modbus]], a data communications protocol used with its PLCs. Modbus has since become a standard open protocol commonly used to connect many industrial electrical devices.<ref>{{cite web \|title=Mobus Networking Guide: Introduction \|url=https://development.libelium.com/modbus_networking_guide/introduction \|website=Libelium.com \|access-date=27 October 2022 }}</ref>		Bedford Associates started a company, '''Modicon, Inc.''',<ref name="b677">{{cite book \| last=Group \| first=Career Communications \| title=US Black Engineer & IT \| publisher=Career Communications Group \| date=1993 \| url=https://books.google.com/books?id=pESCcEtfrusC&dq=modicon%2520inc&pg=PA42 \| access-date=2025-06-09 \| page=}}</ref> dedicated to developing, manufacturing, selling, and servicing this new product, which they named '''{{visible anchor\|Modicon}}''' (standing for "modular digital controller"). One of the people who worked on that project was [[Dick Morley]], who is considered to be the father of the PLC.<ref name=":1">{{Cite web\|url=https://www.isa.org/standards-and-publications/isa-publications/intech-magazine/2003/august/cover-story-50th-anniversary-leaders-of-the-pack/\|title=Leaders of the pack\|last=Strothman\|first=Jim\|date=2003-08-01\|website=ISA\|url-status=live\|archive-url=https://web.archive.org/web/20170808184918/https://www.isa.org/standards-and-publications/isa-publications/intech-magazine/2003/august/cover-story-50th-anniversary-leaders-of-the-pack/\|archive-date=2017-08-08\|access-date=2020-02-24}}</ref> The Modicon brand was sold in 1977 to [[Gould Electronics]] and later to [[Schneider Electric]], its current owner.<ref name=":0" /> About this same time, Modicon created [[Modbus]], a data communications protocol to be used with its PLCs. Modbus has since become a standard open protocol commonly used to connect many industrial electrical devices.<ref>{{cite web \|title=Mobus Networking Guide: Introduction \|url=https://development.libelium.com/modbus_networking_guide/introduction \|website=Libelium.com \|access-date=27 October 2022 }}</ref>

	One of the first 084 models built is now on display at Schneider Electric's facility in [[North Andover, Massachusetts]]. It was presented to Modicon by [[General Motors\|GM]], when the unit was retired after nearly twenty years of uninterrupted service. Modicon used the 84 moniker at the end of its product range until after the 984 made its appearance.<ref>{{cite book \|last=Chakraborty \|first=Kunal \|title=Industrial Applications of Programmable Logic Controllers and SCADA \|date=2016 \|publisher=Anchor Academic Publishing \|location=Hamburg \|isbn=978-3960670247 }}</ref>		One of the first Modicon 084 models built is now on display at Schneider Electric's facility in [[North Andover, Massachusetts]]. It was presented to Modicon by [[General Motors\|GM]], when the unit was retired after nearly twenty years of uninterrupted service. Modicon used the 84 moniker at the end of its product range like Modicon Micro 84 and Modicon TSX CSY 84 until after the 984 made its appearance.<ref>{{cite book \|last=Chakraborty \|first=Kunal \|title=Industrial Applications of Programmable Logic Controllers and SCADA \|date=2016 \|publisher=Anchor Academic Publishing \|location=Hamburg \|isbn=978-3960670247 }}</ref>

	===Allen-Bradley===		===Allen-Bradley===
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	[[File:PLC Control Panel.png\|thumb\|upright\|Control panel with PLC (gray elements in the center). The unit consists of separate elements, from left to right: power supply, controller, relay units for input and output.]]		[[File:PLC Control Panel.png\|thumb\|upright\|Control panel with PLC (gray elements in the center). The unit consists of separate elements, from left to right: power supply, controller, relay units for input and output.]]

	The main difference compared to most other computing devices is that PLCs are intended for and therefore tolerant of more severe environmental conditions (such as dust, moisture, heat, cold), while offering extensive [[input/output]] (I/O) to connect the PLC to [[sensor]]s and [[actuator]]s. PLC input can include simple digital elements such as [[limit switch]]es, analog variables from process sensors (such as temperature and pressure), and more complex data such as that from positioning or [[machine vision]] systems.<ref>Harms, Toni M. & Kinner, Russell H. P.E., ''Enhancing PLC Performance with Vision Systems''. 18th Annual ESD/HMI International Programmable Controllers Conference Proceedings, 1989, p. 387-399.</ref> PLC output can include elements such as indicator lamps, sirens, [[electric motor]]s, [[pneumatic]] or [[hydraulic]] cylinders, magnetic [[relay]]s, [[solenoid]]s, or analog outputs. The input/output arrangements may be built into a simple PLC, or the PLC may have external I/O modules attached to a fieldbus or computer network that plugs into the PLC.~~<!--[[User:Kvng/RTH]]-->~~		The main difference compared to most other computing devices is that PLCs are intended for and therefore tolerant of more severe environmental conditions (such as dust, moisture, heat, cold), while offering extensive [[input/output]] (I/O) to connect the PLC to [[sensor]]s and [[actuator]]s. PLC input can include simple digital elements such as [[limit switch]]es, analog variables from process sensors (such as temperature and pressure), and more complex data such as that from positioning or [[machine vision]] systems.<ref>Harms, Toni M. & Kinner, Russell H. P.E., ''Enhancing PLC Performance with Vision Systems''. 18th Annual ESD/HMI International Programmable Controllers Conference Proceedings, 1989, p. 387-399.</ref> PLC output can include elements such as indicator lamps, sirens, [[electric motor]]s, [[pneumatic]] or [[hydraulic]] cylinders, magnetic [[relay]]s, [[solenoid]]s, or analog outputs. The input/output arrangements may be built into a simple PLC, or the PLC may have external I/O modules attached to a fieldbus or computer network that plugs into the PLC.

	The functionality of the PLC has evolved over the years to include sequential relay control, motion control, [[process control]], [[distributed control system]]s, and [[computer network\|networking]]. The data handling, storage, processing power, and communication capabilities of some modern PLCs are approximately equivalent to [[desktop computer]]s. PLC-like programming combined with remote I/O hardware, allows a general-purpose desktop computer to ~~overlap some PLCs~~ in certain applications. Desktop computer controllers have not been generally accepted in heavy industry because desktop computers run on less stable operating systems than PLCs, and because the desktop computer hardware is typically not designed to the same levels of tolerance to temperature, humidity, vibration, and longevity as ~~the processors used in~~ PLCs. Operating systems such as Windows do not lend themselves to deterministic logic execution, with the result that the controller may not always respond to changes of input status with the consistency in timing expected from PLCs. Desktop logic applications find use in less critical situations, such as laboratory automation and use in small facilities where the application is less demanding and critical.{{citation needed\|date=November 2014}}		The functionality of the PLC has evolved over the years to include sequential relay control, motion control, [[process control]], [[distributed control system]]s, and [[computer network\|networking]]. The data handling, storage, processing power, and communication capabilities of some modern PLCs are approximately equivalent to [[desktop computer]]s. PLC-like programming combined with remote I/O hardware allows a general-purpose desktop computer to serve as a PLC in certain applications.{{citation needed\|date=November 2014}} Desktop computer controllers have not been generally accepted in heavy industry because desktop computers run on less stable operating systems than PLCs, and because the desktop computer hardware is typically not designed to the same levels of tolerance to temperature, humidity, vibration, and longevity as PLCs.<!--[[User:Kvng/RTH]]-->

	===Basic functions===		===Basic functions===

imported>GhostInTheMachine: removed Category:Wikipedia articles with ASCII art using HotCat

2025-06-01T12:01:57Z

removed Category:Wikipedia articles with ASCII art using HotCat

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Programmable logic controller - Revision history

imported>Kvng: review: link scope. add link. no need to single out Windows. rm unnec and inaccessible cite (many other live sources are available if we think we need multiple here). disconnection is not only mitigation suggested.

imported>Grayfell: Undid revision 1307638403 by Buuzbashi (talk) Not a reliable source. Please do not add spam

imported>Kvng: review: ce for clarity. rm rep, unsourced.

imported>GhostInTheMachine: removed Category:Wikipedia articles with ASCII art using HotCat