The document discusses various advanced control systems used in process control and instrumentation, including on-off controllers, feed-forward control, feedback control, ratio control, adaptive controllers, and cascade control. Each system is explained in terms of its operation, advantages, disadvantages, and common applications, emphasizing their roles in maintaining desired performance in industrial processes. It provides insight into the mechanics of how these controllers adjust outputs based on input variables, aiming for optimal control and efficiency.

1. ADVANCED
CONTROL SYSTEM
P R O C E S S C O N T R O L A N D I N S T R U M E N TAT I O N
B Y
A N G E L Y N N
A N G E L E N A
Y U N U S
L O R E T TA
V I M A L A N

2. INTRODUCTION
Advanced control comes into
play from the level of basic
control through that of
process optimization.
Advanced systems provide
generalized models that
automate regulatory and
constraint control as well as
process optimization.

3. ON-OFF
CONTROLLER
N A M E : A N G E L Y N N G R A C E J O S E P H
I D : 1 1 0 3 1 4 2 0 1 9

4. ON OFF CONTROLLERS
Also known as
bang-bang
controllers and
uses hysteresis.
Simple type of
feedback
controllers.
Used to control
temperature.
A thermostat
controlling a
heater is a
common example.

5. ON OFF CONTROLLERS
The output causes change in process variable.
Hence due to effect of output, the process variable again starts
changing but in reverse direction.
When it crosses the preset level, the output valve of the system is
again fully open to give 100% output.
This cycle of closing and opening of output valve continues till the
said on-off control system is in operation.

7. WATER TANK USING TEMPERATURE
CONTROL
On/off temperature control of water in a tank

8. WATER TANK USING TEMPERATURE
CONTROL
The thermostat is
set to 60°C.
The thermostat
would have an
upper and lower
switching point.
This 2°C (±1°C) is
known as the
switching
differential.
The temperature
of the tank
contents will fall
to 59°C before
the valve is asked
to open and will
rise to 61°C
before the valve
is instructed to
close.

9. ON OFF SWITCHING ACTION OF THE
THERMOSTAT

10. ON OFF SWITCHING ACTION OF THE
THERMOSTAT

11. ON OFF SWITCHING ACTION OF THE
THERMOSTAT
From this point onwards, the water temperature in the tank continues
to fall until, at point D (59°C), the thermostat tells the valve to open.
Steam is admitted through the coil but again, reaching its trough of
undershoot at point E.
The difference between the peak and the trough is known as the
operating differential.
The switching differential of the thermostat depends on the type of
thermostat used.

12. ON OFF CONTROLLER
If the controlled condition is
outside the bandwidth, the
output signal from the
controller is either fully on or
fully off, acting as an on/off
device.
If the controlled condition is
within the bandwidth, the
controller output is turned on
and off relative to the
deviation between the value
of the controlled condition
and the set point.
Controlled condition = set
point; ON time will be = OFF
time
Controlled condition < set
point; ON time will be > OFF
time
Controlled condition > set
point; ON time will be < OFF
time

13. FAN CONTROLLING SCHEME OF
TRANSFORMER COOLING SYSTEM.
When transformer runs with such a load, the temperature of the electrical power
transformer rises beyond the preset value .
As the cooling fans run, the forced air decreases the temperature of the
transformer.
When the temperature (process variable) comes down below a preset value, the
control switch of fans trip and fans stop supplying forced air to the transformer.
Again when during rising, the temperature crosses the preset value, the fans
again start rotating to cool down the transformer.

14. FAN CONTROLLING SCHEME OF
TRANSFORMER COOLING SYSTEM.

15. • There is always a non zero time delay for closing and opening action of controller
elements.
• This time delay is known as dead time.
• Actual response curve differs from the above shown ideal response curve.

16. ADVANTAGES & DISADVANTAGES
Advantages
• It is simple and very low cost.
• This is why it is frequently found on domestic type
applications such as central heating boilers and heater fans.
Disadvantage
• The operating differential might fall outside the control
tolerance required by the process.

17. FEED-FORWARD
CONTROL SYSTEM
N A M E : A N G E L E N A R A N I F R A N C I S
I D : 1 0 0 0 0 3 2

18. Is a mechanism
in a system that
monitors
performance
inputs rather
than its outputs.
Prevents or
minimizes
problems before
they occur.
The control
variable
adjustment is
not error-based.
It is based on
knowledge
about the
process.

19. Block diagram of feed-forward system

20. ADVANTAGES
Takes corrective
action before the
process is upset.
Does not affect
system stability.
Theoretically
capable of
“perfect control”.

21. DISADVANTAGES
Requires more
knowledge of
the process to
be controlled.
Disturbance
must be
measured.

22. APPLICATIONS
• SHELL AND TUBE HEAT EXCHANGER
Shell and tube heat exchanger which heats up liquid
water using steam.

23. APPLICATIONS
• EVAPORATOR

24. FEEDBACK CONTROL
SYSTEM
N A M E : A N G E L E N A R A N I F R A N C I S
I D : 1 0 0 0 0 3 2

25. Feedback loops take the system output into
consideration, which enables the system to
adjust its performance to meet a desired
output response.
Contains a measuring element.
Positive feedback has the property that
signals tend to reinforce themselves, and
grow larger.
Negative feedback occurs when some
function of the output of a system tends to
reduce the fluctuations in the output.

27. ADVANTAGES
Corrective
action occurs
regardless of
the source
and type of
disturbances.
Requires little
knowledge
about the
process (A
process
model is not
necessary).

28. DISADVANTAGES
Takes no
corrective
action until a
deviation in
the controlled
variable
occurs.
Incapable of
correcting a
deviation from
set point at
the time of its
detection.
For frequent
and severe
disturbances,
process may
not settle out.
Theoretically
not capable of
achieving
“perfect
control.”

29. APPLICATIONS
• HEAT EXCHANGER

30. APPLICATIONS
• SIMPLE BINARY DISTILLATION COLUMN

31. APPLICATIONS
• HOME FURNACE

32. EXAMPLE QUESTION
• CONTINUOS STIRRED TANK REACTOR(CSTR)

33. RATIO CONTROL
N A M E : M U H A M M A D Y U N U S
I D :

34. WHAT IS RATIO CONTROL?
A common
application for ratio
control is to combine
or blend two feed
streams to produce a
mixed flow with a
desired composition
or physical property.
The ratio control
architecture is used
to maintain the flow
rate of one stream in
a process at a
defined or specified
proportion relative to
that of another.

35. The conceptual diagram
above shows that the flow
rate of one of the streams
feeding the mixed flow,
designated as the wild feed,
can change freely.
Its flow rate might change
based on product demand,
maintenance limitations,
feedstock variations, energy
availability, the actions of
another controller in the
plant, or it may simply be that
this is the stream we are least
willing to manipulate during
normal operation.
The other stream shown
feeding the mixed flow is
designated as the controlled
feed. A final control element
(FCE) in the controlled feed
stream receives and reacts to
the controller output signal,
COc, from the ratio control
architecture.
While the conceptual
diagrams in this article show
a valve as the FCE, we note
that other flow manipulation
devices such as variable
speed pumps or compressors
may also be used in ratio
control implementations.

36. RELAYS IN THE RATIO ARCHITECTURE
As the above diagram
illustrates, we measure
the flow rate of the
wild feed and pass the
signal to a relay,
designated as RY in the
diagram. The relay is
typically one of two
types:
A ratio relay, where
the mix ratio is entered
once during
configuration and is
generally not available
to operations staff
during normal
operation.
A multiplying
relay (shown), where
the mix ratio is
presented as an
adjustable parameter
on the operations
display and is thus
more readily accessible
for change.

37. FLOW FRACTION (RATIO) CONTROLLER
A classic example of ratio
control is the blending of an
additive into a process stream.
As shown below an octane
booster is blended with
straight-run gasoline stream
being produced by an
atmospheric distillation
column.
For any number of reasons, the
production rate of straight-run
gasoline will vary over time in a
refinery.
Therefore, the amount of
octane booster required to
produce the desired octane
rating in the mixed product
flow must also vary in a
coordinated fashion.

39. Rather than using a relay, we present an
alternative ratio control architecture based on a
flow fraction controller (FFC).
The FFC is essentially a “pure” ratio controller in
that it receives the wild feed and controlled
feed signals directly as inputs.
A ratio set point value is entered into the FCC,
along with tuning parameters and other values
required for any controller implementation.

40. RATIO RELAY OR FLOW FRACTION
CONTROLLER
The flow fraction (ratio) controller is a preconfigured option in many modern computer based DCS or
advanced PLCcontrol systems.
It provides exactly the same functionality as the ratio relay combined with a single-input single-output controller
as discussed above.
The choice of using a relay or an FFC is a practical matter.
The entered ratio multiplier value in a relay is not a readily accessible parameter. It therefore requires a greater
level of permission and access to adjust.
Consequently, the use of the ratio relay has the advantage (or disadvantage depending on the application) of
requiring a higher level of authorization before a change can be made to the ratio multiplier.

41. ADAPTIVE
CONTROLLER
N A M E : M A R I A L O R E T T A L A W R E N C E
I D : 1 0 0 0 3 3 9

42. WHAT IS AN ADAPTIVE CONTROLLER?
Adaptive control is the
control method utilized by a
controller which must adjust
to a controlled system with
parameters which change,
or are at first uncertain.
For instance, as an airplane
flies, its mass will gradually
diminish as a consequence
of fuel utilization; a control
law is required that adjusts
to such evolving conditions.

44. Algorithmic Program Control

45. ADAPTIVE CONTROL IN PHOSPHATE
INDUSTRY
Main Control
Objective:
To keep the moisture content of
the dried phosphate close to a
constant desired value, and at
the same time to minimize the
energy consumption, despite
feed flow rate variations and
variable moisture content of the
damp phosphate.
The drying
process is non-
linear in nature.

47. TYPES OF CONTROLLERS
PID with
Gain
Scheduling:
Gain scheduling is a PID
enhancement that facilitates
the control of a process with
gains and time constants that
vary according to the current
value of the process variable.

48. TYPES OF CONTROLLERS
Autotuner:
• An autotuner is often a PID controller where the control
parameters are automatically tuned only at commissioning. I.e. a
sequence of step responses or a relay type of control in order to
find an appropriate parameter setting.

49. TYPES OF CONTROLLERS
Adaptive
PID:
A controller which adjusts the
PID parameters continuously
and automatically while the
process is running. The
tuning is done systematically
as when needed.

50. TYPES OF CONTROLLERS
General
Adaptive
Regulators:
The can operate with as many as
20 regulator parameters. The large
number of regulator parameters
means that, in addition to the PID
functions, it automatically
performs compensation for time
delays, complex dynamics, process
disturbances and feed-forward
control.

51. APPLICATIONS
Catalytic
Fluidized Bed
Reactor
Distillation
Columns
pH
Neutralization
Process
Textile and
Leather
Industry
Others:
• Aeroplanes
• Ship Steering

52. ADVANTAGES & DISADVANTAGES
Advantages:
• Parameters can be
changed quickly in
response to changes in
plant dynamics
• Very easy to apply
Disadvantages:
• The design required for
its implementation is
enormous.

53. CASCADE
CONTROL
NAME : VIMALAN RAVICHANDRAN
ID : 1000335

54. CASCADE CONTROL BLOCK DIAGRAM

55. INTRODUCTION
The simplest cascade control scheme involves two control loops that use two
measurement signals to control one primary variable.
In such a control system, the output of the primary controller determines the set point
for the secondary controller.
The output of the secondary controller is used to adjust the control variable.
Generally, the secondary controller changes quickly while the primary controller
changes slowly.
Once cascade control is implemented, disturbances from rapid changes of the
secondary controller will not affect the primary controller. [ Extracted from : Wikipedia ]

56. In a double loop cascade system, the action of the secondary loop
on the process should be faster than that of the primary loop.
This ensures that the changes made by the primary output will be
reflected quickly in the process and observed when the primary
control variable is next measured.

57. There must
be a clear
relationship
between the
measured
variables of
the primary
and
secondary
loops.
The
secondary
loop must
have
influence
over the
primary loop.
Response
period of the
primary loop
has to be at
least 4 times
larger than
the response
period of the
secondary
loop.
The major
disturbance
to the system
should act in
the primary
loop.
The primary
loop should
be able to
have a large
gain, Kc.

59. Setpoint - temperature desired for the water in the tank
Primary controller (master) - measures water temperature in the tank and asks the secondary controller for more or
less heat
Secondary controller (slave) - measures and maintains steam flow rate directly
Actuator - steam flow valve
Secondary process - steam in the supply line
Inner loop disturbances - fluctuations in steam supply pressure
Primary process - water in the tank
Outer loop disturbances - fluctuations in the tank temperature due to uncontrolled ambient conditions, especially
fluctuations in the inflow temperature
Secondary process variable - steam flow rate
Primary process variable - tank water temperature

60. In the water heater example, the tank temperature controller would be primary since it defines
the setpoint that the steam flow controller is required to achieve. The water in the tank, the
tank temperature, the steam, and the steam flow rate would be the primary process, the
primary process variable, the secondary process, and the secondary process variable,
respectively (refer to the Cascade Control Block Diagram). The valve that the steam flow
controller uses to maintain the steam flow rate serves as the actuator which acts directly on
the secondary process and indirectly on the primary process.[ Extracted from : controleng.com
]

61. ADVANTAGES
The secondary
controller can
correct the
disturbance
affecting the
secondary variable ,
before a
pronounced
influence is felt by
the secondary
variable.
Closing the control
loop around the
secondary part of
the process reduces
the phase lag seen
by the primary
controller, resulting
in increased speed
of response

62. DISADVANTAGES
The extra sensor
and controller
tend to increase
the overall
equipment costs.
Cascade control
systems are also
more complex
than single-
measurement
controllers,
requiring twice
as much tuning.

63. REFERENCES
• K. S. Narendra and A. M. Annaswamy, Stable Adaptive Systems. Englewood Cliffs, NJ:
Prentice Hall, 1989; Dover Publications, 2004.
• S. Sastry and M. Bodson, Adaptive Control: Stability, Convergence and Robustness. Prentice
Hall, 1989.
• http://www.hindawi.com/journals/jcse/2012/827353/
• http://www.pages.drexel.edu/~kws23/tutorials/MRAC/MRAC.html
• https://www.linkedin.com/pulse/fundamentals-cascade-control-hamzeh-ahmadi
• https://controls.engin.umich.edu/wiki/index.php/CascadeControl
• http://www.controleng.com/single-article/fundamentals-of-cascade-
control/bcedad6518aec409f583ba6bc9b72854.html
• http://newton.ex.ac.uk/teaching/CDHW/Feedback/ControlTypes.html#OnOffCtl
• https://www.quora.com/What-is-a-bang-bang-controller
• http://newton.ex.ac.uk/teaching/CDHW/Feedback/Technical-Info.html

64. THANK YOU