Birla Institute of Technology & Science, Pilani  Hyderabad
Process Control
CHE C473 473

Spring 2016
Control System Design Based on
Frequency Response Analysis
Chapter 14
Frequency response concepts and techniques play an important
role in control system design and analysis.
ClosedLoop Behavior
In general, a feedback control system should satisfy the fo
Birla Institute of Technology & Science, Pilani  Hyderabad
Process Control
CHE C473 473

Summer 2015
Spring 2006
Process Dynamics, Operations, and Control
Problem Set 11
10.450
Dont misapply correct formulas! If you encounter a question about stability, dont start
writing formulas until youve understood the process and the system. For example, determine
Birla Institute of Technology & Science, Pilani  Hyderabad
Process Control
CHE C473 473

Summer 2015
Spring 2006
Process Dynamics, Operations, and Control
Problem Set 7
10.450
This problem set allows us to update the simulator with a full PID controller algorithm. We then
calculate the performance of a first order system under PI control. We can compare
Birla Institute of Technology & Science, Pilani  Hyderabad
Process Control
CHE C473 473

Summer 2015
Spring 2006
Process Dynamics, Operations, and Control
Problem Set 9
10.450
This problem set reviews the old procedure of estimating closedloop stability by the Bode
method, as well as tuning by gain and phase margins. The pretext is a change of controlle
Birla Institute of Technology & Science, Pilani  Hyderabad
Process Control
CHE C473 473

Summer 2015
Spring 2006
Process Dynamics, Operations, and Control
Problem Set 6
10.450
A metal block is to be kept at temperature Tsp. The value of Tsp is occasionally changed. A
check of the Biot number convinces you that the temperature will be spatially uniform.
F
Birla Institute of Technology & Science, Pilani  Hyderabad
Process Control
CHE C473 473

Summer 2015
Spring 2006
Process Dynamics, Operations, and Control
Problem Set 8
10.450
This problem set concerns representing nonlinear processes with linear system models. Our
exothermic reactor can exhibit multiple steadystates for some values of the input variabl
Birla Institute of Technology & Science, Pilani  Hyderabad
Process Control
CHE C473 473

Summer 2015
Spring 2006
Process Dynamics, Operations, and Control
Problem Set 5
10.450
The tank is 1 m tall and 60 cm in diameter. The flow to the tank varies unpredictably and
without regular pattern, but has historically been between 0.06 and 0.085 m3 min1. We des
Birla Institute of Technology & Science, Pilani  Hyderabad
Process Control
CHE C473 473

Summer 2015
Spring 2006
Process Dynamics, Operations, and Control
Problem Set 3
10.450
(1) Your new proportional controller arrives from eBay. On one end, the controller has an input
port that is to be fed a signal that ranges from 0 to 100%. Beside it is a set point
Birla Institute of Technology & Science, Pilani  Hyderabad
Process Control
CHE C473 473

Summer 2015
Spring 2006
Process Dynamics, Operations, and Control
Problem Set 2
10.450
(1) Sketch a firstorder step response: mark off increments on the abscissa as multiples of the
time constant; mark off the ordinate as a fraction of the longterm response. This i
Birla Institute of Technology & Science, Pilani  Hyderabad
Process Control
CHE C473 473

Summer 2015
Spring 2006
Process Dynamics, Operations, and Control
10.450
Problem Set 1
(1) Equation (2.2.4) gives the response of a firstorder system to a step input. Let the initial
condition y(0) be zero. Let the step occur at t = 0. Complete this table:
t/
0
1
2
Birla Institute of Technology & Science, Pilani  Hyderabad
Process Control
CHE C473 473

Summer 2015
Overview of Control System Design
Chapter 10
General Requirements
1. Safety. It is imperative that industrial plants operate safely
so as to promote the wellbeing of people and equipment
within the plant and in the nearby communities. Thus, plant
safety
Birla Institute of Technology & Science, Pilani  Hyderabad
Process Control
CHE C473 473

Summer 2015
Fuzzy Logic Control
BITS Pilani
Pilani Campus
Pratik N Sheth
Department of Chemical Engineering
Fuzzy logic Control
It is a general feedback control technique that utilizes the
qualitative information
Qualitative information means
Hot, cold, ok, too hot
Birla Institute of Technology & Science, Pilani  Hyderabad
Process Control
CHE C473 473

Summer 2015
BITS Pilani
Pilani Campus
PID Controller: Design,
Tuning and Trouble
shooting
Pratik N Sheth
Department of Chemical Engineering
Contents
Lag Dominant Models
Dr Pratik N Sheth, Dept of Chemical Engg, BITS Pilani, Pilani Campus
Lag dominant Models
First
Birla Institute of Technology & Science, Pilani  Hyderabad
Process Control
CHE C473 473

Summer 2015
BITS Pilani
Pilani Campus
Control System Design
Based on Frequency
Response Analysis Pratik N Sheth
Department of Chemical Engineering
Contents
Closed Loop Behavior
Bode Stability Criterion
Dr Pratik N Sheth, Dept of Chemical Engg, BITS Pilani, Pilani C
Birla Institute of Technology & Science, Pilani  Hyderabad
Process Control
CHE C473 473

Summer 2015
BITS Pilani
Pilani Campus
Inferential Control
Selective Control
Nonlinear Control System
Pratik N Sheth
Department of Chemical Engineering
Inferential Control
If Controlled variable can no t be measured online
Eg. Product composition measurement,
Feed ba
Birla Institute of Technology & Science, Pilani  Hyderabad
Process Control
CHE C473 473

Summer 2015
Cascade Control
BITS Pilani
Pilani Campus
Pratik N Sheth
Department of Chemical Engineering
Problems 16.1 and 16.5
16.1
Based on secondary measurement time lag
16.5
Based on decision making for combination of feed forward and Cascade Control
strategy
Dr
Birla Institute of Technology & Science, Pilani  Hyderabad
Process Control
CHE C473 473

Summer 2015
Feed forward and Ratio
Control
BITS Pilani
Pilani Campus
Pratik N Sheth
Department of Chemical Engineering
Feedforward Controller Design
Based on Dynamic Models
Dr Pratik N Sheth, Dept of Chemical Engg, BITS Pilani, Pilani Campus
Feedforward Controller
Birla Institute of Technology & Science, Pilani  Hyderabad
Process Control
CHE C473 473

Summer 2015
BITS Pilani
Pilani Campus
PID Controller: Design,
Tuning and Trouble
shooting
Pratik N Sheth
Department of Chemical Engineering
Contents
Performance Criteria for Closed loop systems
Model based design methods
Direct Synthesis Method
Internal model Contr
Birla Institute of Technology & Science, Pilani  Hyderabad
Process Control
CHE C473 473

Summer 2015
Spring 2006
Process Dynamics, Operations, and Control
Problem Set 10
10.450
This problem set attempts to create a realistic context for obtaining a process model. It then
explores how you might use the model. All the operations themselves are straightforw
Birla Institute of Technology & Science, Pilani  Hyderabad
Process Control
CHE C473 473

Summer 2015
BIRLA INSTITUTE OF TECHNOLOGY AND SCIENCE, PILANI
SECOND SEMESTER 20072008
COMPREHENSIVE EXAMINATION
Course No.: CHE C441
Date: 02.05.2008
Course Name: Process Control
Maximum Marks: 80
I/C: Hare Krishna Mohanta
Duration: 3 hours
Note: Answer all parts o
Birla Institute of Technology & Science, Pilani  Hyderabad
Process Control
CHE C473 473

Spring 2016
Feedforward and Ratio Control
Chapter 15
In Chapter 8 is was emphasized that feedback control is an
important technique that is widely used in the process industries.
Its main advantages are as follows.
1. Corrective action occurs as soon as the controlle
Birla Institute of Technology & Science, Pilani  Hyderabad
Process Control
CHE C473 473

Spring 2016
Frequency Response Analysis
Chapter 13
Sinusoidal Forcing of a FirstOrder Process
For a firstorder transfer function with gain K and time constant ,
the response to a general sinusoidal input, x ( t ) = A sin t is:
y (t ) =
(
+1
KA
2 2
e t / cos t + s
Birla Institute of Technology & Science, Pilani  Hyderabad
Process Control
CHE C473 473

Spring 2016
Development of Dynamic Models
Chapter 2
Illustrative Example: A Blending Process
An unsteadystate mass balance for the blending system:
rate of accumulation rate of rate of
=
of mass in the tank mass in mass out
(21)
1
or
d (V )
dt
= w1 + w2 w
(22)
Birla Institute of Technology & Science, Pilani  Hyderabad
Process Control
CHE C473 473

Spring 2016
Laplace Transforms
Chapter 3
Important analytical method for solving linear ordinary
differential equations.
 Application to nonlinear ODEs? Must linearize first.
Laplace transforms play a key role in important process
control concepts and techniques.
Birla Institute of Technology & Science, Pilani  Hyderabad
Process Control
CHE C473 473

Spring 2016
Transfer Functions
Convenient representation of a linear, dynamic model.
Chapter 4
A transfer function (TF) relates one input and one output:
x (t )
X (s)
system
y (t )
Y (s)
The following terminology is used:
x
y
input
output
forcing function
respons
Birla Institute of Technology & Science, Pilani  Hyderabad
Process Control
CHE C473 473

Spring 2016
More General Transfer Function Models
Poles and Zeros:
Chapter 6
The dynamic behavior of a transfer function model can be
characterized by the numerical value of its poles and zeros.
General Representation of ATF:
There are two equivalent representatio
Birla Institute of Technology & Science, Pilani  Hyderabad
Process Control
CHE C473 473

Spring 2016
Chapter 5
Dynamic Behavior
In analyzing process dynamic and process control systems, it is
important to know how the process responds to changes in the
process inputs.
A number of standard types of input changes are widely used for
two reasons:
1. They ar
Birla Institute of Technology & Science, Pilani  Hyderabad
Process Control
CHE C473 473

Summer 2015
Lecture 14, 4/28/2012
Chapter 10:
Material Balances for Processes Involving Reactions
Objectives:
1. Carry out a degree of freedom analysis
2. Formulate and solve material balances using (a) species balances and (b)
element balances
3. Understand how the
Birla Institute of Technology & Science, Pilani  Hyderabad
Process Control
CHE C473 473

Summer 2015
100507 Exam 2 Materials and Energy Balances
ANSWERS ON SEPARATE SHEETS. NAME IN THE UPPER RIGHT CORNER OF EACH
PAGE AND NUMBER THE PAGES. (LEAVE (TOP LEFT) ROOM FOR A STAPLE)
(Gas constant, g, and periodic table are given at the end.)
1)* Titanium dioxide