CBE 491 (CBE 433)

Last lecture: 3 Dec 2012 Final: TBA

Introduction and Review: Review feedback control Block diagram P & ID (process and instrumentation diagrams) Examples and exercises Homework

Feedback Control measure some property compare to setpoint decide what to do change another property Controlled Variable Control Algorithm Manipulated Variable Change in the Manipulated Variable affects the Controlled Variable! Feedback control: Upset happens Measured variable changes Controller responds Examples: ? Solicit ideas on how a controller works… i.e. house furnace….

Block Diagram Feedback Control Loop measure some property compare to setpoint decide what to do change another property Loads Flowrate Temp or Level Process Action Measure Feedback Control Loop error Decision Compare SP

P & ID Symbols (App. A)

P & ID Symbols (App. A)

Examples

Sketch P&ID for one of the Examples:

ID: Process lines…..Control loops

Example: * *1136 W/m2-K

Controlled Variables: Manipulated Variables:

Controller Action

Valve Action

Thermodynamic Behavior