--- title: Process variable slug: process-variable qid: snapshot: enwiki-001353006237 content_hash: license: CC BY-SA 4.0 source: https://en.wikipedia.org/w/index.php?oldid=1353006237 tags: [10362896, 20476424, 22913167, 22970273, 23118434, 23468805, 23603337, 24043274, 24745122] --- # Process variable > [!note] Provenance > Snapshot `enwiki-001353006237` · content root `…` > Derived from · Licensed CC BY-SA 4.0 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 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 (SP). 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 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 (SP). ==Control system use== used to maintain PV = SP]] Measurement of process variables is essential in control systems to controlling a process. The value of the process variable is continuously monitored so that control may be exerted. Four commonly measured variables that affect chemical and physical processes are: pressure, temperature, level and flow, but there are in fact a large number of measurement quantities which, for international purposes, use the International System of Units (SI) 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 PID controller. ==References==