Controllers Flashcards
It is a type of control mode wherein the controller produces an output signal that
is directly proportional to the error
Proportional control
In a P-controller, the Kc
is the controller’s ____
proportional gain or sensitivity
is another term used instead of gain. It is defined as the error (expressed as a percentage of
range of measured variable) required to move the valve from fully closed to fully open.
Proportional Band or Bandwidth
These controllers that instruct either use a fully open or fully closed valve
ON-OFF Controllers
They are also sometimes called switches.
ON-OFF Controllers
On-Off controllers are simulated when the Kc values are ___
very high
employing proportional control
only produces _____ in the steady state response of the control system
offset
Offset is decreased by ____ Kc however it makes the response sluggish and more oscillatory.
increasing
It is a type of control mode wherein the controller produces an output signal that is directly proportional to the integral of the error
Integral Control
Integral control is also sometimes called
reset control or floating control
In an integral mode of control, the main parameter (τ1) is calIed the ____
integral time
The reciprocal of (τ1) is called ____
reset time
It is a type of control mode wherein the controller produces an output signal that
is directly proportional to the derivative of the error
Derivative Control
Derivative control is also sometimes called
rate action, pre-act control and
anticipatory control.
The main parameter in derivative control is τd which is called the ____
derivative time.
A phenomenon of producing
a very aggressive control action due to a sudden change in the error
derivative kick
_____ action is dependent on the value of the error
Proportional control
_____ action is dependent on the length of time of the error.
Integral control
______action is dependent on the rate of change of the error
Derivative control
It is a type of control mode herein the controller produces an output signal that is directly
proportional to the error, its duration and its rate of change.
Proportional-Integral-Derivative (PID) Control
What are the characteristics of a good control system?
Stable closed-loop system
Good disturbance rejection
Good set-point tracking
Elimination of steady-state
offset
Avoidance of excessive control
action
Robust control system
is the characteristic of a control
system to provide rapid and
smooth responses to disturbance and set point
changes with little, if any,
oscillation.
Performance
is the characteristic of a control system to provide satisfactory
performance for a wide range
of process conditions and a
reasonable degree of model
inaccuracy
Robustness
It is the output of a control system for a set point change. An excellent set point tracking for a system would mean an acceptable _____
Servo Response
is the output of a system for
disturbances. As much as
possible, disturbance rejection
means the system reverts back
to its original steady state
response after the introduction
of an unsustained disturbance.
Regulatory Response
Type of controller tuning that is based on a process model
approximation
Model-Based Designs
Type of controller tuning that is done after process installation and during actual process run.
Online Tuning
These controller design techniques base the parameters of the PID Controllers and their
settings on the approximation to the actual system.
Model-Based Designs
two commonly employed
techniques for Model-Based Designs
Direct Synthesis (DS) Method
Internal Model Control (IMC)
These are controller tuning techniques which are employed after the physical installation of the equipment and the production line.
Online Tuning
two commonly employed
techniques for Online Tuning
Ziegler–Nichols (Z-N)
Cohen–Coon(C-C)
An alternative to Ziegler-Nichols tuning is the more conservative _____ settings
Tyreus-Luyben (T-L)
transient output of the
system is also called the
_____
process reaction curve
The ZN tuning technique is also
associated with
Closed Loop Online Tuning
Continuous Cycling Method
The CC tuning technique on the
other hand is also known as
Open Loop Online Tuning
Step Test Method
Process Reaction Curve
Method
The three most common
mathematical measurement of
performance are
Integral of the Absolute Error
(IAE)
Integral of the Squared Error
(ISE)
Integral of the Time-Weighted Absolute Error (ITAE)
The ___ gives a performance
measurement that is directly
proportional to the error.
IAE
The ___ penalizes larger errors and usually results to more aggressive controller settings.
ISE
The ____ penalizes longer errors and usually results to less aggressive controller settings
ITAE
