Process variable

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search

Template:Short description Script error: No such module "about". Script error: No such module "Unsubst".

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 set-point (SP).[1]

Control system use

File:Set-point control.png
Block diagram of a negative feedback control system 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.Script error: No such module "Unsubst". 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

<templatestyles src="Reflist/styles.css" />

  1. Script error: No such module "citation/CS1".

Script error: No such module "Check for unknown parameters".


Template:Asbox