Process Control Complete Study Review Rated A
A method to monitor and adjust specific process parame-
Process control
ters to maintain desired values.
provide the capability to monitor and adjust specific
process parameters to maintain desired values. In some
Process control systems
nuclear facilities, these ?????????? are known as instrumen-
tation and control systems.
the system output is monitored by a process sensor, which
automatic systems feeds the measurement signal back to a controller at the
input of the system
consists of an operator manually adjusting a final control
manual control element based on the indicated value of the controlled
variable
A control signal that can only be in either the on or the ott
On/Ott Control
state; no intermediate state is possible.
Examples of ??????? are sump pumps, air compressors, and
on/ott control
heaters.
The control signal response is proportional to the mag-
Continuous Control nitude of the error so the final control element operates
continuously within pre-defined limits.
A common example of ???????? is cruise control on a vehicle.
A cruise controller senses the speed of the vehicle, com-
pares this speed to a desired reference, and then accel-
erates or decelerates the vehicle, as required. The cruise
continuous control controller can vary the rate of acceleration depending on
how far the vehicle's speed is from the setpoint. While the
proportional control function responds to the magnitude
of the error, an integral control function is needed to
restore the actual value to the setpoint
,Process Control Complete Study Review Rated A
A process control specifically designed to prevent damage
Protective action
to systems and equipment.
can be designed for manual operator control, fully auto-
Process control systems
matic control, or automatic protective action
This function determines if there is a ditterence (called an
error) between the measured parameter (vehicle speed)
Compare and what was entered as the desired setpoint vehicle
speed. For our purposes here, we will assume there is a
ditterence, and you are either going too fast or too slow.
This function determines if the error is positive or negative,
Compute and what output is needed to the engine (speed up or
slow down).
is normally considered the first function in Process Control.
It is the actual monitoring of a parameter that is desired
Measure
to be controlled. In our example, this would be the mea-
surement of the vehicle speed.
This function involves the ettort performed by the engine
to make the actual speed match the setpoint speed. The
engine speeds up or slows down until the measured
speed matches the setpoint speed. Feedback is the term
Correct used for the constant input of the measured process para-
meter (speed) to achieve the desired setpoint. Some de-
sign methods provide a varied (faster or slower) correction
based on how far the measured process parameter is from
the desired setpoint.
Feedback The constant input of the measured process parameter.
also known as the primary element, senses change in the
measured variable and provides an output proportional
to the magnitude of the measured parameter. Typically
, Process Control Complete Study Review Rated A
the ??????? is exposed to the process being measured. For
example, an orifice plate, which is a plate with a hole in
Detector it, is a primary element installed in a pipe. The ditterential
pressure of the flow through the hole in the plate is mea-
sured to calculate the flow rate.
receives output from the detector and converts it to a
standard electronic or pneumatic signal range for trans-
mission to the controller. ????????????? are considered sec-
ondary elements because they convert the output of the
The transducer or transmitter
primary element. Depending on the application and the
instrumentation used, the function of the ???????????? (and
possibly the detector) may be performed by a single de-
vice.
receives the transducer or transmitter signal and performs
two discrete functions. First, it compares the measured
Controller variable to the setpoint and generates an error signal if
they are not equal. Second, it computes the required out-
put response based on the selected controller functions
The process variable that is being maintained at a speci-
Controlled variable
fied value or within a specified range.
The final control element manipulates the process para-
Final Control Element
meter
works to restore balance or decrease the ettect of a dis-
turbance to the process, as shown in the graphic below.
Feedback The measurement of the controlled variable is fed to the
controller. The controller then outputs to the final control
element, which corrects the process
Information concerning the current state of the process
closed-loop control is fed back to the control system from the measuring
element - the detector
A method to monitor and adjust specific process parame-
Process control
ters to maintain desired values.
provide the capability to monitor and adjust specific
process parameters to maintain desired values. In some
Process control systems
nuclear facilities, these ?????????? are known as instrumen-
tation and control systems.
the system output is monitored by a process sensor, which
automatic systems feeds the measurement signal back to a controller at the
input of the system
consists of an operator manually adjusting a final control
manual control element based on the indicated value of the controlled
variable
A control signal that can only be in either the on or the ott
On/Ott Control
state; no intermediate state is possible.
Examples of ??????? are sump pumps, air compressors, and
on/ott control
heaters.
The control signal response is proportional to the mag-
Continuous Control nitude of the error so the final control element operates
continuously within pre-defined limits.
A common example of ???????? is cruise control on a vehicle.
A cruise controller senses the speed of the vehicle, com-
pares this speed to a desired reference, and then accel-
erates or decelerates the vehicle, as required. The cruise
continuous control controller can vary the rate of acceleration depending on
how far the vehicle's speed is from the setpoint. While the
proportional control function responds to the magnitude
of the error, an integral control function is needed to
restore the actual value to the setpoint
,Process Control Complete Study Review Rated A
A process control specifically designed to prevent damage
Protective action
to systems and equipment.
can be designed for manual operator control, fully auto-
Process control systems
matic control, or automatic protective action
This function determines if there is a ditterence (called an
error) between the measured parameter (vehicle speed)
Compare and what was entered as the desired setpoint vehicle
speed. For our purposes here, we will assume there is a
ditterence, and you are either going too fast or too slow.
This function determines if the error is positive or negative,
Compute and what output is needed to the engine (speed up or
slow down).
is normally considered the first function in Process Control.
It is the actual monitoring of a parameter that is desired
Measure
to be controlled. In our example, this would be the mea-
surement of the vehicle speed.
This function involves the ettort performed by the engine
to make the actual speed match the setpoint speed. The
engine speeds up or slows down until the measured
speed matches the setpoint speed. Feedback is the term
Correct used for the constant input of the measured process para-
meter (speed) to achieve the desired setpoint. Some de-
sign methods provide a varied (faster or slower) correction
based on how far the measured process parameter is from
the desired setpoint.
Feedback The constant input of the measured process parameter.
also known as the primary element, senses change in the
measured variable and provides an output proportional
to the magnitude of the measured parameter. Typically
, Process Control Complete Study Review Rated A
the ??????? is exposed to the process being measured. For
example, an orifice plate, which is a plate with a hole in
Detector it, is a primary element installed in a pipe. The ditterential
pressure of the flow through the hole in the plate is mea-
sured to calculate the flow rate.
receives output from the detector and converts it to a
standard electronic or pneumatic signal range for trans-
mission to the controller. ????????????? are considered sec-
ondary elements because they convert the output of the
The transducer or transmitter
primary element. Depending on the application and the
instrumentation used, the function of the ???????????? (and
possibly the detector) may be performed by a single de-
vice.
receives the transducer or transmitter signal and performs
two discrete functions. First, it compares the measured
Controller variable to the setpoint and generates an error signal if
they are not equal. Second, it computes the required out-
put response based on the selected controller functions
The process variable that is being maintained at a speci-
Controlled variable
fied value or within a specified range.
The final control element manipulates the process para-
Final Control Element
meter
works to restore balance or decrease the ettect of a dis-
turbance to the process, as shown in the graphic below.
Feedback The measurement of the controlled variable is fed to the
controller. The controller then outputs to the final control
element, which corrects the process
Information concerning the current state of the process
closed-loop control is fed back to the control system from the measuring
element - the detector
