Instrumentation and Process Control Flashcards
________ refers to the use of instruments to monitor and regulate process
conditions.
Instrumentation
The process variables that are commonly monitored in a refinery are:
.
Pressure
.
Temperature
.
Level
.
Flow
List various components of a control loop and their functions
Controllers:
-Compare measured process variable values with the
corresponding set points to identify process deviations
Sensing Devices:
-Measure process variables
-Are of various types because these devices are used to
measure variables having different characteristics
Transmitters:
-Transfer signals or measurements from sensing devices to
controllers
-Can be an inherent part of sensing devices that provide
the measurement and output signals
Indicators or
Recorders:
-Receive measured signals from transmitters
-Facilitate observation and recording of process variable
values
End Devices:
-Final elements of the process control loop that directly
affect the process
-For example, control valve, the common type of end
device found in process units
List various components of a control loop and their functions
Controllers:
-Compare measured process variable values with the
corresponding set points to identify process deviations
Sensing Devices:
-Measure process variables
-Are of various types because these devices are used to
measure variables having different characteristics
Transmitters:
-Transfer signals or measurements from sensing devices to
controllers
-Can be an inherent part of sensing devices that provide
the measurement and output signals
Indicators or
Recorders:
-Receive measured signals from transmitters
-Facilitate observation and recording of process variable
values
End Devices:
-Final elements of the process control loop that directly
affect the process
-For example, control valve, the common type of end
device found in process units
1) ______ pressure scales are used to measure absolute pressure.
2) ______ zero is a condition where air and pressure are not available.
a. vacuum
b. gauge
c. theoretical
d. absolute
1) d. absolute
2) c. theoretical
______is any pressure below atmospheric pressure. Using 14.7 psia as a starting point
a. gauge
b. vacuum
c. theoretical
d. absolute
b. vacuum
pressure is used to measure the pressure difference between a system and the
atmosphere.
a. gauge
b. vacuum
c. theoretical
d. absolute
Gauge
What elastic device is most often used in pressure gauges?
a. bourdon springs
b. bellows elements
c. diaphragms
a. bourdon springs
What are 4 indirect level measurement devices?
.
Pressure-sensitive level gauge
.
Bubbler system
.
Nuclear system
.
Radar system
A _______ level measurement system operates by directing radiation from a high-energy
radiation source through the contents of the vessel to a detector.
The ______ system consists of a high-energy radiation source and
a. bubbler
b. radar
c. nuclear
d. absolute
c. nuclear
What level measurement system uses electromagnetic waves to measure level?
a. bubbler
b. radar
c. nuclear
d. absolute
b. radar
A _______ cell measures the difference between two related pressures, such
as atmospheric pressure and hydrostatic pressure.
These cells can be used
to measure liquid level in both pressurized and nonpressurized tanks.
a. atmospheric pressure
b. differential pressure
c.
differential pressure
An _______ _______ is a simple type of restriction used to measure the flow rate of fluid through
a pipe. An_______ _____ is a thin plate with a hole in the center.
a. dampener
b. orifice plate
orifice plate
- The differential pressure across the ______ ______ is measured using a differential
pressure cell.
The differential pressure cell is connected to a local flow rate indication device to
obtain the flow rate through the pipe.
Alternatively, the differential pressure cell can be connected to a transmitter that
sends a signal to a remote device. The remote device, located in a control room,
records the flow rate data.
orifice plate
______ flow meters use electrical conductivity of the fluid to measure the flow.
a. transducer
b. electrode
c. magnetic
d. conductivity
magnetic
A ___ ____ _____ measures the mass per unit time, such as kilograms per second or
pounds per second, of the fluid flowing through the device.
a. mass flow meter
b. turbine flow meter
c. flume flow meter
mass flow meter
____ ____ are the most common type of liquid concentration analyzers. ___ is a
measure of the hydrogen ion concentration of a solution and represents the acidity or
alkalinity of a solution.
pH analyzers
_______ are devices that change or convert one type of signal to another type of
signal.
Transducers
For pneumatic transmitters and transducers, you need to ensure that the required air
pressure is supplied to the instrument. This air is called _____ _____ and is produced by
a separate system to ensure clean dry air is supplied to instruments.
instrument air
A ______ indicator is located at a distance from the equipment or system where the
process takes place. An instrument located in a control room is an example of this.
a. console
b. remote
c. local
remote
____ are used to alert personnel when the values of process variables are outside the
normal operating range.
Alarms
What is the 4 step procedure for high level alarm testing?
To test the high level alarm:
1. Close the bottom and top root valves of the separator.
2. Open the vent valve to the relief system.
3. Fill the level glass with water or test fluid until the level switch trips the alarm.
4. Note the actual level at which the alarm trips.
Controllers can also be identified by their _____ ______ .
For example, a recording and indicating controller controls the process variable, provides
a visual indication of the process variable, and records the values of the process variable.
a. additional functions
b. federal id
c. chevrons id system
additional functions
The _____ of an instrument is the degree of conformity of a measurement to a standard
or true value.
a. accuracy
b. sensitivity
c. speed of response
d. reproducibility
a. accuracy
_______ in instrumentation is the ability to provide accurate readings constantly.
a. accuracy
b. sensitivity
c. speed of response
d. reproducibility
d. reproducibility
