Agung PrayitnoElectrical Eng. Dept – UBAYA

INDUSTRIAL AUTOMATION I

Industrial Automation I(2012 Global Planning)

Global PictureProcess Control

Global PictureProgrammable Logic Controller

A Process Control SystemDefinition

Automatic process control is concerned with maintaining process variables : temperatures, pressures, flows, compositions, and the like at some desired operating value .

Process(dynamic in nature)

Related to:-Safety- Produc Quality- Production Rate

Variables need to be controlled

A Process Control SystemAn illustration : Heat Exchanger (Manual Control)

The objective is to heat the process fluid from some inlet temperature Ti(t) up to a certain desired output temperature T(t). The energy gained by the process fluid is provided by the latent heat of condensation of the steam.

How to control

manually?

Define variables that can change, causing the outlet temperature to deviate from its desired value!

Problems of manual control?

A Process Control SystemAn illustration : Heat Exchanger (Automatic Process Control)

Need to understand symbols and identifications!- Process Flow Diagram (PFD)- Piping & Instrumentation Diagram (P&ID)

Need to know basic control loop components:- Sensor-Transmitter- Controller- Final Control Element

A Process Control SystemTerms and Objectives

Controlled Variable(In this case: Outlet Temperature)

Set Point

Manipulated Variable(In this case : Steam Valve Position)

Disturbance(Steam Temp)

Disturbance(Inlet Temp)

Disturbance(Process flow)

Disturbance(Ambient condition)

Regulatory and Servo Control

Regulatory control refers to systems designed to compensate disturbances

Servo control refers to systems designed to follow a desired profile (set point may change as a function of time)

Piping & Instrumentation Diagram (P&ID)

Feedback Control

TCV10

How to conver P&ID to Block Diagram

TT10

TC10 TCV10

FeedForward Control

Multiloop ControlFeedback + Feedforward Control

Laboratory WorkDeveloping Piping & Instrumentation Diagram

� Make P&ID of the compact workstation Process Control System !