http://debianws.lexgopc.com/wiki143/index.php?action=history&feed=atom&title=Process_variableProcess variable - Revision history2026-05-01T00:09:49ZRevision history for this page on the wikiMediaWiki 1.43.1http://debianws.lexgopc.com/wiki143/index.php?title=Process_variable&diff=3630620&oldid=previmported>K6ka: Reverted edit by 176.29.150.243 (talk) to last version by Kvng2024-07-12T12:36:07Z<p>Reverted edit by <a href="/wiki143/index.php?title=Special:Contributions/176.29.150.243" title="Special:Contributions/176.29.150.243">176.29.150.243</a> (<a href="/wiki143/index.php?title=User_talk:176.29.150.243&action=edit&redlink=1" class="new" title="User talk:176.29.150.243 (page does not exist)">talk</a>) to last version by Kvng</p>
<p><b>New page</b></p><div>{{Short description|Value of a given part of a monitored or controlled process}}<br />
{{about|the engineering indicator|the mathematical concept used in thermodynamics|process function}}<br />
{{more citations needed|date=May 2022}}<br />
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In [[control theory]], a '''process variable''' ('''PV'''; also '''process value''' or '''process parameter''') is the current measured value of a particular part of a process which is being monitored or [[Control system|controlled]]. An example of this would be the temperature of a furnace. The current temperature is the process variable, while the desired temperature is known as the [[setpoint (control system)|set-point]] (SP).<ref name=Bequette><br />
{{cite book |author=B. Wayne Bequette | title = Process Control: Modeling, Design, and Simulation | publisher =Prentice Hall Professional | year= 2003 | page = 5 |url=https://books.google.com/books?id=PdjHYm5e9d4C&pg=PA5 |isbn = 9780133536409 }}<br />
</ref><br />
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==Control system use==<br />
[[File:Set-point control.png|thumb|Block diagram of a [[Negative feedback|negative feedback control system]] used to maintain PV = SP]]<br />
Measurement of process variables is essential in [[control system]]s to controlling a process. The value of the process variable is continuously monitored so that control may be exerted.<br />
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Four commonly measured variables that affect chemical and physical processes are: [[pressure]], [[Thermodynamic temperature|temperature]], level and flow.{{citation needed|date=December 2011}} but there are in fact a large number of measurement quantities which for international purposes use the [[International System of Units]] (SI)<br />
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The SP-PV error is used to exert control on a process so that the value of PV equals the value of the SP. A classic use of this is in the <br />
[[PID controller]].<br />
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==References==<br />
{{Reflist}}<br />
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{{DEFAULTSORT:Process Variable}}<br />
[[Category:Control theory]]<br />
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{{Tech-stub}}</div>imported>K6ka