Instrumentation set 2
The United States industry standard for the input signal of pneumatic recorders is:
3 to 15 psi
Nodes
A DCS system divides production control in a plant into several subparts called...
protects from sudden release of pressurized fluids
A Jerguson type valve:
piping and instrumentation
A _______ ________ diagram is a schematic diagram of the relationship between instruments, controllers, piping, and system equipment.
a strip consisting of two alloys
A bimetallic thermometer is a thermal expansion thermometer that uses _______ to measure temperature.
pressure
A bourdon tube is used to measure which process variable?
low
A bright, shiny object that reflects light generally has a _______ emissivity.
manual or remotely operated switch, a relay and a servomotor, a plumb bob for a weight, and a cable
A cable and weight system consists of a ________.
What is the digital element used to deny a burner ignition sequence if the fuel gas pressure is abnormal, there is no air flow, or there is no pilot flame?
AND gate
Remote
An instrument located away from the process.
Electronic
An instrument powered by electricity.
A ladder diagram is read
Both B and C
What does an I/P transducer do?
Converts current to a pneumatic signal
I/O stands for inputs and others.
False
Pressure
Force applied to a unit area.
Heat always flows from [x] temperature to [y] temperature
Hot/ cold
Sometimes out of necessity, a controller will be performing the control functions for several processes; this controller is referred to a a(n) __?__.
Shared controller
Temperature
Specific degree of hotness or coldness as indicated on a reference scale.
When one controller is used to control two final elements, it is known as:
Split-range
Troubleshooting
Systematically examining, localizing, and diagnosing equipment malfunctions or anomalies.
temperature
The wavelength and amplitude of the radiation emitted by a body changes with the _____ of the body.
True
Upstream pressure to a valve may increase or decrease causing the actual flow rate through the valve to vary as well
continuous
_______ level measurement is a method of measuring level over a range of values.
Absolute
_______ pressure is measured with a perfect vacuum as the zero point of the scale.
Pascal's
________ law states that pressure applied to a confined static fluid is transmitted with equal intensity throughout the fluid.
Hysteresis
_________ is a property of physical systems that do not react immediately to the forces applied to them or do not return completely to their original state.
Force
___________ is anything that changes or tends to change the state of rest or motion of a fluid.
A system installed to provide protection of equipment from line-to-ground fault damage is called:
a ground-fault circuit interrupter
One method of oxygen analysis focuses on the:
a. paramagnetic properties of oxygen b. dissolvability of oxygen in water
pH < 7
acidic
Calibration defined
apply a known input span to the instrument and adjust the instrument to correspond with the known values.track performance of the unit output when a known input is applied to it. Compare readings of a known value with readings of the unknown value.
Redundant controllers in a distributed control system reside:
as a hot standby at the central processor
electrical device consisting of one or more cells that converts chimical energy into electrical energy
battery
Uses two dissimilar metals that are bonded together and expand and contract at different rates when exposed to temperature changes
bimetallic strip
During troubleshooting, radio communication usually takes place between the field technician and the?
board technician
"_____ Math allows for AND, OR, XOR basic comparative functions with bits in the registers."
boolean
an automatic device for stopping the flow of current in an electric circuit as a safety measure
breaker
switchlike device used to keep electrical voltage from exceeding recommended load
breaker
A _____ allows us to measure the head pressure of a liquid without the pressure sensor coming in contact with the process fluid
bubbler
Carbon dioxide is produced commercially:
by extraction from the atmosphere
A chemical, classified as a base, harms a human body by causing all the following EXCEPT:
calcification of the tongue
Testing to determine and instrument's accuracy is called _____
calibration
device used to restore batteries to proper electrical charge
charger
Capacitance transducer
checks pressure with a measurement diaphragm
A turbidity analyzer is used to determine the _____ of a liquid.
cloudiness
on/off control
control element is moved from one of two fixed positions depending on being above or below the setpoint. common in home heating systems
overide control
control scheme does nothing until process reaches some kind of limit; activates and takes control of the process until parameters are back in normal operating range
All of the following items are transducer elements EXCEPT a:
control valve
integral control function
controller output calculation based on how long the PV has deviated from the SP
derivtive control function
controller output calculation is based on how fast the error is changing
feedforward control loop
controller output is based on a relationship between the measured variable and the manipulated variable, using this information to predict a future error and prevent it
proportional control function
controller output is porportional to the deviation from the setpoint
I/P conversion-
current to pneumatic
Which of the following is another name for a synchronous time switch?
dashpot timer
"A ____ is a network of computer networks, other devices, and switching systems used for the transfer of digitized information."
data highway
Before performing a continuity check on a circuit, the instrument technician MUST be sure that the circuit is:
de-energized
DCS eliminates the loss of accuracy that results from A/D conversion
false
Measures IR radiation
infrared
The term topology is often used with digital control systems to describe:
interconnection of control components
first alarm triggered when a process variable falls below a predetermined set point
low alarm
pH = 7
neutral
When bench calibrating a temperature RTD transmitter, the instrument technician should apply:
resistance
The third wire of a 3-wire RTD is used for _____.
resistance compensation
A _________ is a common temperature measuring device.
resistance temperature device
breaker
safety device used to provide protection against over current
Ideally, functional verification of a loop is done through:
transmitter simulation
"An ESD is a system consisting of interlocks, breakers, sensors, and other equipment responsible for shutting down equipment in an extremely abnormal situation in order to protect the equipment and reduce the risk of catastrophe"
true
PLCs function as
Both A and B
Hydrostatic Head Pressure
P=h x SG Units: h=inches of height p= in w.c.
Hydrostatic head pressure is independent of the diameter of the vessel/tubing.
PI= (H1 x SG) + (H2 x SG)
True
PLC logic refers to computer instructions that are basically on/off commands based on true/false assessments
Monitoring Production Emergency Shut-Down Ratio Control
PLC's are used for...
Stand Alone Controls Only A Part of an Integrate Control System
PLC's function as...
Relays and Drum Switches
PLCs now handle functions formerly performed by...
Final control element
Part of a control loop that actually makes change to a process.
Toggle/HOA (hand off auto)
Physical style of switch: 3 possible positions.
Limit
Physical style of switch: used t verify the physical state of a piece of equipment in the process. comes int direct contact with the device it is monitoring.
True
T or F A Seebeck voltage cannot be measured directly.
False
T or F A background temperature thermometer measures infrared radiation using one IR detector.
In MOST cases, the cable shield will be attached:
at one end
_______ is measured using a barometer
atmospheric pressure
The _______________ will signal the generator to turn on in the event of power failure from the primary power supply
automatic transfer switch
electromechanical device that switches an electrical load between two separate power sources
automatic transfer switch
The most common way to indicate the level of a tank is by _____.
percent level
PLCs are used for
All of the above
Measurement of the consumption of fuel
Combustion
What type of valve MOST precisely controls flow?
Needle
What does the "PI" in PI-209 stand for?
Pressure Indicator
" Ladder is scanned left to right, top to bottom."
True
pH > 7
basic
Transformers are used to change current
false
Teflon tape should be applied clockwise from the:
first thread back
device used to change DC to AC
inverter
"Because of redundancy, a DCS is extremely reliable"
true
Feedback control-
"
Deviation-
" The difference between the setpoint and the controlled variable under dynamic (changing) conditions."
Shielding-
" controls external electromagnetic interference (EMI), foil, mesh, or woven wire.
I/E conversion-
" current to voltage"
Shutdown switches-
"Can actuate a circuit that shuts down a process. in failsafe conditions they can be used to deactivate a circuit to shut down part of the process."
Smart Instruments-
"Instruments that have one or more microprocessors or "smart chips" included in their electronic circuitry so they may be programmed and have diagnostic capability."
Direct acting controller-
"a controller whose output signal value increases or decreases as the controller input signal value increases( increased input = increased output) or decreases.
Relay-
"a device that "boosts," maintains, or controls the flow of a signal so it can be properly received."
chart recorder-
"a device that physically or electronically record data that process and instrument technicians can use to troubleshoot process trends and instrumentation problems."
Switch-
"a mechanical or electrical device that is used to operate or energize mechanical or electrical circuits for alarm, shutdown, or control purposes using a predetermined operating point or setpoint."
Pneumatic transmission-
"a signal transmission method that uses compressed air/gas to create signal."
Digital transmission-
"a signal transmission method that uses digital devices to create a signal."
Electrical transmission-
"a signal transmission method that uses electrical devices to create a signal."
Mechanical transmission-
"a signal transmission method that uses mechanical methods to create a signal."
Process variable switch-
"a type of switch that actuates when a predetermined value of a process variable (pressure, temperature, level, flow, and analytical) is present."
Proximity switch-
"a type of switch that requires the presence of an object or device to facilitate its operation such as a magnetic coupling or decoupling."
Zeroing out-
"adjusting a measuring instrument to the proper output value for a zero measurement signal."
N.O. switch-
"closes its contacts when powered."
Process field switches can be purchases as-
"normally open (N.O.) contact, normally closed (N.C.) contacts, or both. When the process condition is met, the contact open and create an open circuit. This type of switch is commonly used in safety systems since it also alarms or shuts down the process when electrical power is lost or when the circuit is cut."
N.C. switch-
"opens when powered."
Integral Action / Reset
"resets" the proportion at set intervals, looks at deviation from setpoint, and how long it has occurred Will drive to setpoint
proximity switches-
"sense the closeness of an object without having physical contact as a limit switch does. This can be done by use of magnetic fields, while others use beams of light. proximity switch can be N.O. or N.C."
A limit switch sensing mechanical motion may be used to-
"sound an alarm, initiate a shutdown, autostart a process, and or/bypass something"
Calibration-
"the act of applying a known input span to an instrument and adjusting the device so that it provides an indication or output corresponding to the known values."
E/I conversion-
"the conversion of a signal from voltage to current."
Dead time-
"the elapse time between the initiation of an input(measured, controlled or manipulated variable) change, or other stimulus and the point at which the resulting response can be measured or observed."
cycling-
"the moving or shifting of a process variable above and/or below the setpoint."
Troubleshooting-
"the process of systematically examining, localizing and diagnosing equipment malfunctions or anomalies.
Autostart switches-
"trigger an autostart sequence when predetermined process conditions are met."
Shutdown switch-
"used to actuate a circuit that shuts down a process."
Vibration switch-
"used to determine the velocity, acceleration, displacement or any combination of these characteristics, for the purpose of predicting wear or impending failure.
Alarm switch-
"used to notify an operator when a process variable enters an abnormal range (high or low) by triggering an alarm (light or annunciator)."
Bypass switch-
"used to override the normal operation of a system or device."
Limit switch-
"used to verify the state or presence of a condition that exists In the process"
Relays-
"when the term is applied to pneumatic (computational) devices, are analog instruments handling continuously variable signals. When applied to electrical devices, relays are discrete, on/off devices."
Strain gauge
"with applied pressure, wires stretch"
Why don't all the standard signal ranges start at ZERO?
-Live Zero is the practice of using non-zero instrument ranges, so that calibration is easier. Live Zero also makes it clear when an instrument is reading at the low end of its scale, and when the instrument is malfunctioning (the zero value).
Calibration
-calibration in the field (zero and span) -check against sight glasses (level) -calibration in the shop (use known standards) a. air pressure b. dead wight testers c. certified thermometers -smart instruments (connect to microprocessor and run diagnostics, made adjustments)
Transmitter common malfunctions
-low voltage from power supply (or air supply with pneumatic instruments) -loss of power -environmental problems (corrosion or excessive humidity) -calibration shifts
Troubleshooting Concepts
1. Divide the loop in half. 2. Know the most likely types of failures/problems (chart page 210) 3. Check calibrations 4. In an instrument loop, the big sections to evaluate are: a. Loop upstream of the controller. b. Controller c. Loop downstream of the controller.
Impulse Tubing Common Malfunctions
1. Plunged or partially plugged tubing. 2. leakage. 3. improperly sized tubing. 4. excessive vibration 5. heat tracing too hot. 6. heat tracing to cold. 7. mechanical damage.
Troubleshooting In The Field
1. Safety-PPE, Safety practices a. hazardous environments b. electricity 2. Communication a. working with control room operators b. working with instrument techs.
Basic troubleshooting steps include:
1." Making sure that the PV indication on the controller corresponds to the true output of the transmitter by having an instrument tech simulate signals on the input to the controller or from the transmitter. 2. Placing the controller in manual and see if the process stabilizes. 3. With the controller still in manual, determining if the controller moves the final control element properly. 4. Confirming that the final control element movement is smooth. 5. Ensuring that the loop I properly tuned ( check tuning parameters."
When multiplying 47.1 X 7.2, then dividing the product by 11.23 the answer should have how many significant digits?
2
A gauge pressure of 195 psi is roughly what in psia?
210
A DCS accepts 1 to 5-volt inputs. The transmitter outputs are 4-20 mA. What type of resistor should normally be installed in the analog input card?
250.0 ohms
vapor-pressure pressure-spring
A ________ thermometer is a pressure-spring thermometer that uses the change in vapor pressure due to the temperature change of an organic liquid to determine the temperature.
bimetallic
A ________ thermometer works because of the difference in expansion coefficient between the metal components fused together into one strip.
guided wave radar
A _________ is a level measuring detector consisting of a cable or rod as the wave carrier extending from the emitter down to the bottom of the vessel and electronics to measure the transit time.
black body calibrator
A ___________ is a device used to calibrate infrared thermometers.
dry well calibrator
A ___________ is a temperature-controlled box where a thermometer can be inserted and the output compared to the known temperature.
sensor
A _______is any device that is sensitive to a change in the measured phenomenon or characteristic.
level, stored electrical energy
A capacitance probe is designed to measure ______ by detecting changes in _________.
Controller common malfunctions
-plugging -water in the air -power loss (in electronic) -water in the device itself -air or electrical power failure -controller needs re-tuning due to change in transmitter span.
Load Change
A change in any variable in the process that affects the value or state of the controlled variable. Somethings changing in the process.
Final control element common malfunctions
-process plugging -corrosion or erosion in the valve -packing leaks -sticking valve -mechanical failure of tubing or valve components. -water in the air line. -water in the device itself. -air or electrical power failure. -I/P or positioner out of calibration.
snubber
A device used to protect a pressure sensing device from over-pressure is called a:
material
A final element is a device that receives a control signal and regulates the amount of ________ or energy in a process.
If an orifice plate is installed backwards in the pipe, it will result in?
A fixed error in the meter output signal the flow characteristics through the orifice plate are dependent on the shape of the opening note the openings are not symmetrical.
Zero Suppression
-transmitter mounted below process. -PV=0 does not equal a sensor reading of 0 -offset the instrument display to account for the higher reading at pv=0 -NOTE: in the field, you can zero the 4-20mA signal in place, but in a bench calibration, you have to account for the pressure that the device will actually sense in the field.
Signal wire common malfunctions
-bad connection -broken wire -too much loop resistance -shielding problems
Thermocouple common malfunctions
-burnout -corrosion -bad connection -delayed response time if used with thermowell without thermo conductive fluid.
If the diaphragm in a pressure transmitter is becoming fouled/coated over time, the sensor may register?
A gradually decreasing pressure reading (reading low) eventually reading 0. As the diaphragm becomes coated, its response is weakened, or dampened. That means it will be registering less pressure than its actually sensing it cant flex as much,. over time this can decrease to a 0 reading.
From left to right and From top to bottom
A ladder diagram is read...
laser beam generator, a timer, and a detector
A laser level instrument is a level measuring instrument consisting of a ______________.
electrical signal
An electronic calibrator generates a(n) ________ that replicates the signal from an electrical thermometer.
emissivity
Blackbody calibrators have a known ______ of nearly 1.0.
-300; 800
Bimetallic thermometers can be used to measure temperatures from _____^F to ____^F.
The numbering system computers and PLCs use to manipulate information is the ____ system.
Binary
The active changing the controller from manual to automatic or vice versa without a significant change in a controller output is called
Bumpless transfer
displacer
Buoyant cylinder connected to a spring or tension measuring device.
Remote set point is a term associated with which control scheme
Cascade
The control scheme that employs two controllers where the output of one controller is the set point of another is called
Cascade control
Reduced Lag Time and Better Control
Cascaded control schemes are used to...
As materials of constructions for a device or piping system, the process fluids, piping materials, and welted parts of instruments MUST be:
Compatible
_____ pressure gauges may be necessary when there is a need to measure pressures below, at , or above atmospheric pressure.
Compound gauge
Unit shut down
Computer failure using Direct Digital Control would likely cause...
Measurement of the molecular components of a liquid or gas
Chromatography
A series DC circuit consists of 4 resistors. The voltage drops across the resistors are: R1=2V, R2=4V, R3=8V, and R4=10V. Which of the following statements is true?
Circuit voltage = 24V
_____ is the manner in which heat moves through solid matter.
Conduction
Measurement of a solution's ability to conduct electricity
Conductivity
Ratio
Control involving one uncontrolled (wild) stream and one controlled stream
Override Control
Control scheme does nothing until process reaches some kind of limit; activates and takes control of the process until parameters are back in normal operating range.
Feed Forward
Controller on one variable uses 'knowledge' from another area to change its response. Predicting the future error, preventing it.
Integral Control Function
Controller output calculation based on how long the PV has deviated fro the SP. How long its been away from the set point.
Derivative Control Function
Controller output calculation is based on how fast the error is changing.
Feed-forward Control Loop
Controller output is based on a relationship between the measured variable and the manipulated variable, using this information to predict a future error and prevent it.
Proportional Control Function
Controller output is proportional to the deviation form set point.
_____ is the transfer of heat through the circulatory motion that occurs in a fluid when there is a difference in temperature from one region to another.
Convection
_____ describes a method of heat movement.
Convection, Conduction, Radiation (all of the above)
On what principle do mass flow meters operate?
Coriolis
The departure from a desired value; the system deviation that exists after the process has been stabilized is called the __?__
Deviation
What term below describes the difference between setpoint and process variable? a: ____ Desired Value b: ____ Actual Value c: ____ Deviation d: ____ Propcess Controller
Deviation
The components that are monitored by video screen are actually __?__ that are used to __?__ a particular function.
Devices Measure
Ladder Diagrams
Diagrams used to describe PLC internal logic are called...
Differential
Difference between measurements taken from two separate points.
Offset
Difference between the setpoint and the controlled variable under steady state conditions.
Which of the followng cannot be classified as an analog signal?
Digital
False
Digital controller require more care in bumpless transfer from manual to automatic
False
Digital instruments show change in a continuous manner
A(n) __?__ signal is often referred to as an on/off switch.
Discrete
A Material Safety Data Sheet (MSDS) has all of the following sections EXCEPT:
Disposal Contractors
Which of the following actuates a proximity switch?
Distance of the process variable from the process switch
DCS stands for:
Distributed Control System
One of the best ways to begin troubleshooting a loop is to first?
Divide the loop in half
One of the best ways to begin troubleshooting an instrument loop is to first?
Divide the loop in half. When you divide the loop in half, you generally break the loop at the controller. Then you can evaluate the controller, and the signals coming to and from the controller. Once you determine which side of the controller is causing the problem, then you can continue to divide that portion of the loop in half. (look at the flow instrument separately from the temperature instruments in a compensated flow loop)
Methods to determine if a sensing or measuring device is malfunctioning include:
Divide the loop into halves until the problem has been isolated to one component. If multiple problems have simultaneously occurred start at the controller.
Temperature is a measure of the average Kinetic [x] of the [y] of a substance. (two word)
Energy/ molecule
Proportional Band
Equals change in input over a change in output, is expressed as a percent %. As PB goes up, the rate of response gets smaller/slower.
Gain
Equals change in output over a change in input. Expressed as a decimal. As Gain goes up, the rate of response gets larger/faster.
A reactors catalyst feed is manipulated due to A predicted load change
Feed forward
A tank level is manipulated because an error signal has developed
Feedback
True
Feedback is a closed loop control strategy while feedforward is an open loop control strategy
Input or Output
Field instruments are usually connected to some type of ___ or ___ device that resides on an Input/Output (I/O) highway
A technology bypassing conventional I/O by using direct communications between smart field devices and the associated control processors is:
Fieldbus
The program that is permanently entered into a PLC processor is called:
Firmware
indicate tank levels, actuate alarms, shutdown switches, or mechanically control valves
Floats can be used to _________.
funnel flow
Flow is where material empties out of the bottom of a silo and the main material flow is down the center of the silo, with stagnant areas at the sides and bottom of the silo is called?
Alarm
Function: notifies when a process variable enters an abnormal range (either high or low)
Shutdown
Function: will actuate a circuit that shuts down the process-usually for an emergency situation.
Autostart
Function: will actuate an automatic process start-up when predetermined conditions are met.
Bypass
Function: will be used to over-ride the normal operation of a system or device.
Measures the chemical composition
GC
Integral control, also known as reset, describes a controller in which the output rate of change is dependent upon the magnitude of the:
Gain
Hydrostatic head pressure
H x SG
All of these
Heat is transferred by _____ from a flame into a boiler to create steam.
convection
Heat transfer that occurs by the movement of a fluid from one place to another caused by a pressure difference is called:
Level
Height of the surface of a material compared to zero reference point.
False
For a digital controller to activate an analog valve only one signal conversion will ever be necessary
Analog Electrical Signal
For an analog pneumatic transmitter to communicate with a digital controller the signal be converted first to an...
Hydrostatic Head
Formula: PI= (H1 x SG) + (H2 x SG) (convert psig to in. w.c.27.7)
temperature scales
Four common ________ ______ are the Fahrenheit, Rankine, Celsius, and Kelvin.
When using a DP transmitter for flow measurement, what is the MOST commonly used PRIMARY element:
Orifice plate
This type of control prevents the constrained variable from exceeding its limit
Override
A drawing that illustrates the physical components of a system, including its piping, valves, and instrumentation, is called a(n):
P&ID
All of the following are loop tuning parameters EXCEPT:
P&ID
Process Variable
Physical style of switch: will actuate when a predetermined process variable or state is exceeded.
Vibration
Physical style of switch: will determine vibration, usually used to predict wear or impending failure in rotating equipment.
Proximity
Physical style of switch; requires the presence of an object or device to activate the circuit-may not come n direct contact with the process.
Trend
Plot of a process variable over time.
A bubbler is used as feedback in what type of system?
Pneumatic
air
Pneumatic pressure refers to the pressure of:
The act of controlling a process variable by hand within the processing area
Local manual control
Derivative Action / Rate, Pre‐act
Looks at how fast the error is changing Predicts where the PV will be in a set amount of time Adjusts response
The resistance measured when verifying connection to ground should be:
Low
What kind of resistance should be present when checking for grounds?
Low or none
A(n) __?__ is defined as any function or operation utilized in the treatment of material.
Process
The information gathered by field measuring devices should accurately portray the working __?__
Process
The main function of an operator station is to collect, monitor, display, alarm, trend and control the _________
Process
The variable for which supply and demand must be balanced - the system under control, excluding the equipment that does the controlling, is called the __?__
Process
Lead-Lag Control
Process is reacting to a change in conditions. Lead/Lag often used to switch between identical equipment. Lead/Lag may also be used to relate two different process variables to each other. Example The second pump in a parallel pump configuration is programmed to start when there is an increase in required process flow.
Any variable property of a process; the part of the process that changes, and therefore needs to be controlled, is called thee __?__
Process variable
PLC is an acronym for ______________
Programmable Logic Controller
difference
Proportional control is a control strategy that uses the ________ between the set point and the process variable.
Ratio Conrtol
Proportioning the rates of flow between two separate flowing streams entering a mixing point
Insulating
Protective covering-prevents heat loss, protects personnel from exposure to hot piping/equipment, and protects piping/equipment from abrasion.
shielding
Mesh or foil is used to encase the transmission wire, and then connected to the grounding wire. this will divert stray signals away form the signal transmission line and reduce interference/noise in the process signal.
Which of the following is a type of gasket used in high-pressure systems?
Metal ring joint
A PLC is controlled by:
Microprocessors
Which test equipment below is MOST suitable for calibrating a temperature transmitter with a thermocouple-sensing element?
Millivolt simulator
A process may include many variables which may have the option of being __?__ or used for __?__.
Monitored Control
Which of the following is not a benefit of PLCs over relay control?
More hardwired devices
Flow
Quantity of fluid moving within a given period of time.
Proportioning the rates of flow between two separate flowing streams entering a mixing point
Ratio control
True
Ratio control differs from cascade control in that ratio loop doesn't receive feedback from the primary loop
True
Ratio control loops are designed to proportion the flow of two or more product streams
Setting the controller to open or close a valve out in the processing area from a control room
Remote manual control/remote automatic control
Cascade
Remote set-point (RSP) is a term associated with which control scheme
Tuning
Setting the controller's parameters of gain, reset, and rate to optimize the control of the process variable.
List four reasons a DCS systems is preferred over an analog based system
Speed Reliability and accuracy Cost effectiveness Space efficiency
One final control element (Valve a) responds to the lower half of the output signal while another (valve B) responds to the upper half of the output signal
Split range
True
T or F A bimetallic temperature element can be used as a temperature switch.
False
T or F A bimetallic thermometer is another name for a pressure-spring thermometer.
true
T or F A boiler operator is typically responsible for control systems that measure temperature, pressure, flow, and other variables.
False
T or F A break point is the temperature at which the resistance of an RTD begins to increase rapidly.
True
T or F A bulk solid is a granular solid, such as gravel, sand, sugar, grain, cement, or other solid material, that can be made to flow.
false
T or F A calorie is the amount of energy necessary to change the temperature of 1 pound of water by 1 degree F from 59 degrees F to 60 degrees F.
True
T or F A capsule is a mechanical pressure sensor consisting of two convoluted metal diaphragms with their outer edges welded together to provide an empty chamber between them.
true
T or F A common source of training on instruments is from the instrument manufacturers.
True
T or F A difference thermocouple is a pair of thermocouples connected together to measure a temperature difference between two objects.
True
T or F A disappearing filament pyrometer can only be used with surfaces that have a visible color change above about 1000^F.
False
T or F A ground loop is an unintended circuit caused by a breakdown of thermocouple insulation.
False
T or F A heat sink is a heat conductor that adds heat to electronic parts by pressure difference.
True
T or F A large number of reference marks enable a liquid-in-glass thermometer that is filled with mercury under pressure.
False
T or F A line scanner IR thermometer is an imager where the temperature measurement at all positions in the image is known.
True
T or F A loss of water in a boiler can lead to the burning out of tubes and/or a boiler explosion.
False
T or F A manometer is an impulse line that is filled with a noncondensing gas.
True
T or F A null-current thermocouple consists of a circuit and a voltage generator that can be adjusted to exactly balance the voltage output of the thermocouple.
False
T or F A paddle wheel switch is a continuous level measuring device consisting of a drive motor and a rotating paddle wheel mounted inside a tank.
True
T or F A pressure transmitter is a pressure transducer with a power supply and a device that conditions and converts the transducer output into a standard analog or digital output.
False
T or F A pressure transmitter is a pressure-sensing device that provides a discrete output (contact make or break) when applied pressure reaches a preset level within the switch.
False
T or F A radiometric thermal imager uses a rotating mirror with a single, very fast response detector or a linear array of IR detectors to measure successive areas with a single stationary device.
true
T or F A reference temperature is a known fixed point needed to define a temperature of the material by a certain amount.
False
T or F A resistance pressure transducer is a mechanical transducer that measures the deformation of a rigid body as a result of the force applied to the body.
False
T or F A strain gauge is a diaphragm pressure sensor with a capacitor as the electrical output element.
false
T or F A technician can stop learning and coast through a job after initial training.
True
T or F A technician should ensure that the proper calibration standard is used.
True
T or F A thermal dispersion sensor's detector monitors the difference in temperature between a heated probe tip and an unheated probe.
True
T or F A thermocouple hot junction is a point where two dissimilar wires are joined.
False
T or F A thermocouple is a temperature-sensitive resistor consisting of solid-state semiconductors made from sintered metal oxides and lead wires, hermetically sealed in glass.
True
T or F A thermocouple junction is a point where the two dissimilar wires are joined.
False
T or F A three-valve manifold is unnecessary because the manometer can open up the process stream without blowing out the manometer fluid.
true
T or F A transducer is a device that converts one form of energy to another, such as converting pressure to voltage.
False
T or F A tuning fork level detector is a point level measuring instrument consisting of a vibrating wire that resonates at a particular frequency and the circuitry to measure that frequency.
True
T or F A two-color IR thermometer is independent of the emissivity of the surface as long as the emissivity of a measured surface is the same for both wavelengths of the two IR detectors.
False
T or F A vapor-pressure pressure-spring thermometer is a pressure-spring thermometer that is filled with mercury under pressure.
false
T or F A variation of the flush diaphragm d/p cell is the double-filled system, which is used with fluids containing high quantities of solids.
True
T or F A water column is a boiler fitting that reduces the movement of boiler water to provide an accurate water level in the gauge glass.
True
T or F A well-type manometer is a manometer with a vertical glass tube connected to a metal well, with the measuring liquid in the well at the same level as the zero point on the tube scale.
true
T or F A wet leg is an impulse line filled with fluid that is compatible with the pressure-measuring device.
False
T or F A whitebody reflects a portion of all wavelengths of radiation equally.
true
T or F Absolute zero pressure is a perfect vacuum.
True
T or F After the high-pressure valve on a three-way manifold is closed during the manometer disconnect process, a manometer can still contain pressurized fluids.
True
T or F An electrical pressure transducer is a device that converts input energy from pressure into output electrical energy.
False
T or F An extended diaphragm d/p cell is a type of level measuring device that uses flanged diaphragm seals and capillary systems.
True
T or F An inclined-tube manometer is a manometer with its measuring column at an angle to the horizontal to reduce the vertical height.
True
T or F Armored gauge glasses are used in boilers and high-pressure vessels.
True
T or F As long as liquid in a tank has a constant density, variations in pressure are caused only by variations in level.
False
T or F At mean sea level, the standard pressure of air is about 27.7 PSI.
True
T or F Bodies that are at thermal equilibrium must balance the energy entering that object with the energy leaving that object.
true
T or F Conduction is a heat transfer method used to remove heat from sensitive electronic parts.
True
T or F Conductivity level probes can only be used with conductive liquids.
False
T or F Continuing education about process control instrumentation is not necessary.
False
T or F Convective energy waves move through air or space while producing heat.
False
T or F Dielectric refers to a property of certain ferrous alloys having dimensions that change in response to magnetic stress.
True
T or F Differential pressure is the difference in pressure between two measurement points in a process.
False
T or F Dry legs can be used to measure the pressure of liquids in pipelines.
False
T or F Final elements are the first element in the control loop.
True
T or F Fluid can be blown out of a manometer by opening the connection to a process too quickly.
True
T or F For RF capacitance continuous level measuring instruments, a vertically suspended capacitance probe can be used for measuring the level in a tank.
False
T or F For accurate temperature measurement, a thermometer should always be immersed in a material just far enough to completely cover the bulb.
False
T or F For ultrasonic point level measurement, a rising liquid fills the gap between two crystals and blocks the signal.
False
T or F Force is the number of unit squares equal to the surface of an object.
true
T or F HVAC technicians are often required to use instruments to take measurements in the field to troubleshoot problems.
True
T or F Head is independent of the shape of a container.
True
T or F Head is the actual height of a column of liquid.
True
T or F Heat transfer is the movement of thermal energy from one place to another.
True
T or F High process temperatures can damage a pressure sensor.
False
T or F Hydraulic pressure is the pressure of air or another gas that is compressed.
False
T or F Hydraulic pressure refers to the pressure of a gas.
True
T or F In applications that use a bimetallic element to make a measurement over a small temperature range, alloys with widely differing rates of thermal expansion are used.
True
T or F Isolating sealing systems have been developed to protect pressure sensors from corrosive fluids.
True
T or F It is more convenient to measure pressure at the bottom of a tank than to measure the actual location of the top of the liquid in a sealed tank.
False
T or F It is not possible to have condensed vapors collecting as liquids in low-pressure connections of d/p cell level measurement applications of pressurized tanks.
True
T or F Laser beams are intense, narrow light beams that can travel long distances.
True
T or F Level measurement is essential for safety systems in boilers and for overflow and spill prevention systems in tanks and silos.
False
T or F Magnetostrictive refers to the ability of an electrical device to store charge as the result of the separation of charge.
true
T or F Metals are generally good conductors of heat.
True
T or F Mixer blades and other objects in the vessel can cause false echoes, and dust in the air above a granular solids surface may absorb the radar signal.
False
T or F Pneumatic pressure is the pressure in a confined hydraulic liquid that has been subjected to the action of a pump.
False
T or F Pressure is anything that changes or tends to change the state of rest or motion of a body.
true
T or F Pressure is independent of the shape of a container and depends only on the properties of fluid and height.
True
T or F Pressure seals with integral sealing liquid should not be disassembled due to the difficulty of restoring that integrity.
False
T or F Probes may be supplied with low-level AC or high-level DC voltage, depending on the nature of the process liquid.
true
T or F Process control instrumentation is the technology of using instruments to measure and control manufacturing, conversion, or treating processes to create the desired properties of materials.
True
T or F Process control is a system that combines measuring and controlling instruments into an arrangement capable of automatic remote action.
True
T or F RF capacitance probe level detectors can operate with granular solids as well as liquids.
False
T or F Radiant heat can be felt through a window because of the emissivity of the window.
False
T or F Ratholing is the process of discharging water and undesirable accumulated material from a boiler.
False
T or F Sensitivity is a gradual change in an element over time when the process conditions are constant.
true
T or F Short courses to help technicians learn new skills are often available at trade shows.
False
T or F Shunt impedance is a circuit that is used to precisely measure an unknown resistance
False
T or F Specific gravity is the ratio of volume of a fluid to volume of a reference fluid.
True
T or F Standard d/p cells used to measure level are susceptible to attack by corrosive fluids or blockage by slurries.
True
T or F The Seebeck effect is a thermoelectric effect where continuous current is generated in a circuit where the junctions of two dissimilar conductive materials are kept at different temperatures.
True
T or F The buildup of process material on the probe sometimes presents a problem because the presence of a coating can act as a dielectric even when the level is below the probe.
True
T or F The electronic circuitry in an ultrasonic receiver measures the transit time and calculates the distance from the receiver to the surface of material.
True
T or F The infrared segment of the electromagnetic spectrum is not visible, but the wavelength of the radiation can be measured.
True
T or F The law of intermediate metals states that the use of a third metal in a thermocouple circuit does not affect the voltage, as long as the temperature of the three metals at the point of junction is the same.
True
T or F The liquid used in liquid-in-glass thermometers is usually mercury, alcohol, or an organic liquid with red dye added to improve visibility.
True
T or F The word "color" in one-color or two-color IR thermometer is misleading because these thermometers measure infrared radiation instead of visible light.
true
T or F There are many trade union training programs that help technicians gain and develop the skills needed to be successful.
True
T or F There can be moisture condensation in the connection piping or tubing between a process and a manometer.
False
T or F There is a single standard definition of the unit "inches of water."
True
T or F Thermal equilibrium is the state in which objects are at the same temperature and there is no heat transfer between them.
False
T or F When a U-tube manometer is used to measure pressure, a single-valve manifold is used with the manometer for easy shutoff and equalizing.
true
T or F a 1' column of water has a pressure of 0.433 PSI, which means that water has a hydrostatic pressure of 0.433 PSI/ft of height.
False
T or F capacitance is the insulating material between the conductors of a capacitor.
True
T or F triple point is the condition where all three phases of a substance - gas, liquid, and solid - can coexist in equilibrium.
Measures the amount of carbon
TOC meter
What is the purpose of the "acknowledge" function in an annunciation panel?
The "acknowledge" function silences an audible alarm. Alarm will still be visible until the alarm condition is corrected and acknowledged. There may be a control that silences the alarm but continues the flashing until the alarm is fully acknowledged. Annunciators may require manual reset, or be configured to automatically reset once the alarm condition is corrected.
latent
If the state of matter changes as a result of heat transfer, you would be observing ________ heat transfer.
What is the most common cause of controller failure?
Improper tuning. Consider the proportional band. proportional band too high means that the controller responds with very small changes proportionally to a process change doesn't react enough. proportional band too low means that the controller will make big changes in response to any process condition that will cause big swings in the controller output.
Multi-Variable Control
Multiple inputs/outputs affect multiple controlled variables; often requires computerized management.
Multiplexer
Multiple signals from field instruments would be forwarded to a controller by a...
Multiple signals from field instruments would be forwarded to a controller by a
Multiplexer
Pneumatic computing relays perform which of the following functions:
Multiplication of air signals
Diagrams to use to describe PLC internal logic are called
Ladder diagrams
In their normal position
Ladder diagrams generally show contacts and relays...
This type of circuit is used to swap the lead role between two equal parallel components, such as compressors and/or evaporators in a refrigerator system
Lead/lag
When used as a film between two surfaces, lubricants will reduce all of the following EXCEPT:
Leakage
material balance
Leaks, lies and line-ups refers to:
length
Level is normally measured in linear units of ______ or translated into units of volume or weight.
volume
Level measurement is often used to measure the ______ of material in a tank or vessel.
Which digital element correlates to a circuit allowing either of two switches to apply power to a light bulb?
OR gate
Measurement of the ratio of reducing agents to oxidizing agents
ORP
Where does the diaphragm of springless, pneumatic actuator control valves use air pressure?
On both sides
Which of the following items describes any pressure below atmospheric pressure?
Vacuum
_____ is the pressure scale that starts at atmospheric pressure and decreases towards theoretical zero pressure?
Vacuum
try cocks
Valves located on a water column that are used to determine boiler water level if a gauge glass is not functional are called?
Flow rates, levels, temperatures, pressures, and more are all read by a controller and the total __?__ for each system may number in the hundreds.
Variables
Which of the following is used to calibrate a DP transmitter?
Wally box
3.47
When a pressure gauge on a boiler is mounted 8' below the top of the water level of the wet leg, the pressure adjustment is _____PSI.
1000
When a pressure of 200 PSI is transmitted equally from one hydraulic cylinder to a load cylinder, the force on the load cylinder piston with an area of 5 square inches is _____ lbs.
A symbol indicating a open/closed circuit
When considering PLCs a gate refers to...
Point level system
Which level measuring system reports only when a target value is achieved?
Multi-skilled
Which maintenance technician is becoming more popular in industry because of offering flexibility and cost-effectiveness?
Cascade Control
The control scheme that employs two controllers where the output of one controller is the setpoint of another
Feedback Control Loop
The controller responds to a shift in the process variable (creating an 'error' when it is different fro the setpoint) by manipulating the process to return to the setpoint.
Which of the following describes span?
The difference between 3 and 15
Dead Time
Time until process begins to respond to a change in controller output. The elapsed time between the initiation of an input and the point at which the resulting response can be measured or observed. Delay, (distance from a signal)
Lag Time
Time until process shifts from one state to another. Example stabilize at a new level or flow rate. How long it actually takes before the actions start.
When commissioning a loop, what is the MOST important reason for the instrument technician to open valves slowly?
To avoid surges
In your own words, explain how you think instrumentation plays a part in process control.
To eliminate human interaction
Feedback is a closed loop control strategy while feed forward is an open loop control strategy
True
Kelvin scale is called an absolute scale because 0 K is the point at which no heat exists.
True
PLC logic refers to computer instructions that are basically on/off commands based on true/false assessment
True
Ratio control differs from Caskay control and that ratio control Luke doesn't receive feedback from the primary loop
True
Ratio control loops are designed to proportion the flow of two or more product streams
True
Smart transmitters have an A/D converter built into the instrument so the instrument can process information within the onboard microprocessor
True
The increased reliability provided by PLCs make up for the increased wiring required
True
The local computer is for each node and a DCS system communicate with a host computer
True
The primary need for instrumentation is to control and monitor process variable.
True
Upstream pressure to a valve may increase or decrease causing the actual flow rate through the valve to vary as well
True
In PLCs, how many possible states do discrete inputs have?
Two
audible or visual signal used to draw attention to problem situations
UPS alarm
in a vacuum
Ultrasonic level measurement cannot be used ________ or with liquids that are covered with foam.
In order to effectively troubleshoot problems within a loop it is necessary to:
Understand how the loop is intended to operate
Computer failure using direct digital control would likely cause
Unit shut down
Process
The main function of an operator station is to collect, monitor, display, alarm, trend and control the ___
DCS
The multi-loop computer controlled system presently used to manage process technology is called...
Density is analyzed using all the following methods EXCEPT:
air bubbler
When bench calibrating a pressure transmitter, the instrument technician should apply:
air pressure in psi
type of electrical current that reverses direction at regular intervals
alternating current
The instrument signal line symbol (------), a broken line with no marks drawn through it, represents:
an electric signal
Please select the situation that does not contribute to instrument failure mode:
an open process variable
Measures absorption of visible light
color analyzer
The primary function of a/an ____ is to configure the DCS with all its hardware devises and control scheme
configuration station
_____ level measurement monitor all level points in the tank
continuous
"if a fixed amount of mass occupies a larger volume, then its density has to _____"
decrease
"if a fixed amount of mass occupies a larger volume, then its density has to_____"
decrease
The greatest inaccuracy of a differential pressure level detector is caused by a change in the
density of the liquid being measured
Specific gravity of a liquid is the ratio of its _____ to the density of _____
density/ water
Specific gravity of a liquid is the ratio of its[x] to deterring the density of [y]
density/ water
_____ is the distance from starting at the surface of a liquid and exe tens downward.
depth
lead/lag control
describes how the process variable is controlled by controlling another; in this scheme one controller is the remote setpoint of another
A chromatograph is used to:
determine the chemical composition of a liquid or gas
triggered when differences between two variables exceeds the set limit
deviation alarm
A _____ transmitter measures the difference between total pressure and vapor space pressure to determine tank level
differential pressure
Gradual change is less likely to occur with _____
digital instruments
electrical current that flows in only one direction
direct current
A _____ measures its own buoyancy force to determine the tank level
displacer
The beveled edge of an orifice plate faces:
downstream
dp=P high- P low
dp= (h x sg) + (I x sg) - (Tx sg)
Zero Elevation
dp=Phigh-Plow dp= (Pgas + H1 x SG + H2 x SG)- (Pgas + H3 x SG)
industrial
With a (an) _______ thermometer, graduations are engraved on metal plates rather than marked or scaled on glass tubes.
Why are the concepts of zero suppression and zero elevation helpful to the process operator?
You could calibrate this system form the even more negative pressure that equals 0 inches of height to the full rage of liquid height. Or you could apply a zero elevation correction to the output of the transmitter, so that it gives you a 0 reading when the process value is zero.
proportional band
[1/Gain] x 100% answer numerically
reluctance
_____ is the property of an electric circuit that opposes a magnetic flux.
forced convection
______ ______ is the movement of a gas or liquid due to a pressure difference caused by the mechanical action of a fan or pump.
natural convection
______ ______ is the unaided movement of a gas or liquid caused by a pressure difference due to a difference in density within the gas or liquid.
insulators
______ are poor conductors of heat.
negative
______ gauge pressure is gauge pressure less than zero.
ISA
______ has developed a comprehensive standard for instrumentation symbols.
pressure
______ is force divided by the area over which that force is applied.
head
______ is the height of a column of liquid above the reference or zero point.
absolute zero
______ is the lowest temperature possible where there is no molecular movement and the energy is at a minimum.
Well drop
______ is the ratio of the area of the tube to the area of the well in a well-type manometer.
gauge
______ pressure is measured with atmospheric pressure as the zero point of the scale.
Hydrostatic
______ pressure is the pressure due to the head of a liquid column.
Absolute zero
______ where there is no molecular movement and the energy is at a minimum.
Thermocouple aging
_______ _______ is the process by which thermocouples gradually change their voltage-temperature curve due to extended time in extreme environments.
change in temperature, pressure, humidity, and composition of gas
_______ affects the speed of the ultrasonic signal.
all of these
_______ cause pressure pulsations in a pipeline.
static
_______ characteristics of an element describe the operation of the element at steady-state conditions when the process is not changing.
On/Off
_______ control is the simplest and most common control strategy.
sensitivity
_______ is an adjustment to the relationship between two IR detectors to compensate for a difference in infrared radiation detection.
Overranging
_______ is subjecting a mechanical sensor to excessive pressure beyond the design limits of the instrument.
Admittance
_______ is the ability of a circuit to conduct alternating current and is the reciprocal of impedance.
temperature
_______ is the degree or intensity of heat measured on a definite scale.
repeatability
_______ is the degree to which an element provides the same result with successive occurrences of the same condition.
bandwidth
_______ is the range of frequencies from the minimum to the maximum value in an FMCW radar level sensor.
A physical foundation for digital logic where 0 Volts DC represents a logic level of zero, and 5 Volts DC represents a logic level of one, is called:
a. transistor-transistor logic b. diode-diode logic
The accuracy of a pressure switch refers to the:
ability of the switch to repeatedly actuate at a given set point
The letters "EL" on a blueprint stand for:
elevation
A loop sheet contains all of the following information EXCEPT:
elevation of instruments
In a properly grounded system:
excess voltage and current are rapidly directed to the earth
Common environmental factors that cause instrumentation malfunction are?
excessive temperatures, corrosion, sudden change in temperature, over-ranging, inclement weather, high humidity, high vibration, mechanical damage
A/an _____ is a module that increases the number of I/O controlled by a PLC. This module does not contain a processing unit.
expander
"Despite playing a critical role in process safety, interlocks can be bypassed without management permission."
false
"Management permissions are not required so that permissives can be bypassed, tampered with, or their duration shortened"
false
"With DCS, the individual nodes communicate with production control via subdivided nodes."
false
A gradual change in instrument readings is easy to diagnose.
false
A standard deviation may be more difficult to recognize and troubleshoot than an abrupt or gradual change.
false
A useful rule of thumb says that a control valve should normally operate between 25% and 75%
false
An abrupt change in the indicating value of a process variable with a corresponding change in the process are indication that a sensor or transmitter is faulty
false
Analyzers are incapable of measuring both quantitative and qualitative properties of a process
false
During abnormal modes the static switch will transfer the load from the bypass to the inverter
false
During normal operation, power will not pass through the ATS.
false
For a DCS node, D/A converts processed signals to digital.
false
For a DCS node, an A/D receives Demux commands
false
For a DCS node, the end elements are forwarded A/D signals
false
Inundation systems spray the area with large quantities of water to dilute the concentration of vapors so they are below the lower explosive limit
false
The UPS will provide power to the control system until utility power is restored.
false
The high voltage power lines typically carry 138KV of direct current (DC).
false
Troubleshooting often utilizes a process of equation simulation
false
Turbine meters operate non- linearly with respect to the volume flow rate
false
a vortex meter is useful for measuring slurries or fluids with high viscosity
false
all the pressure loss across an office plate is coverable
false
materials flow from a low pressure area to a high pressure area
false
pH measurement differs from Oxidation Reduction Potential in that ORP measurement is specific to hydrogen ion concentration and pH measurement is thought of as being specific to free electron concentration
false
the Prandtl number is a mathematical computation that decries flowing fluids numerically
false
The backwards installation of an orifice plate will result in:
fixed error in the output signal
a _____ senses the surface of a material to determine the level
float
Pressure is defined as _______ per unit _______
force /area
The term "span adjustment" refers to the adjustment of the
gain of an instrument
which unit of measurement is commonly associated with total volumetric flow?
gallons
which unit f measurement is commonly associated with a volumetric flow rate?
gallons per minute
An opacity analyzer is used to determine how much particulate matter is in a _____________ sample
gas
device that uses mechanical energy to create electrical energy
generator
Line markings on the heads of bolts and screws indicate:
grade
A confined space is identified as:
having limited entry and exit
[x] [y] refers to the static pressure produced by the weight of the liquid above the point at which the pressure is being measured
head /pressure
_____ is the distance from a zero reference point in a container to the surface of the material
height
level is the [x] of a liquid with reference to a [y] point
height /zero
first alarm triggered when a process variable rises above a predetermined set point
high alarm
When an electronic D/P cell is calibrated, the simulated input pressure should be connected to the transmitter's:
high side
triggered when a process variable rises above a predetermined maximum set point
high-high alarm
shutdown circuit designed to detect dangerous condition and safely shut down a process or piece of equipment
interlock
DC voltage converts to AC voltage as it passes through the ___________.
inverter
In bubbler system measuring level from the bottom to the top of the vessel the dip tube is installed in a vessel with its open end:
just above the bottom of the vessel
A DCS is preferred over earlier analog based systems for all the following reasons except:
less interaction needed between instrumentation techs and operator
Spectrophotometry is the quantitative study of electronic spectra; a spectrophotometer measures _____ absorption
light
a[x] [y] is a transducer used to convert force or weight into an electrical signal
load/ cell
"A/an ____ is usually connected to the DCS through some type of gateway or security devices that allows read-only data to be available to engineers, maintenance, and operations personnel"
local area network
The drawing that shows how similar devices are to be installed and connected is an instrument:
loop diagram
Penetrating oils are used to:
loosen rust and corrosion
triggered when a process variable drops below a predetermined minimum set point
low-low alarm
At high altitudes, the atmospheric pressure is:
lower than the atmospheric pressure at lower altitudes
In order to take direct control over a process, the controller should be placed in:
manual control
The operation modes of a loop controller are:
manual, automatic, and cascade
Density is defined ad [x] per unit [y]
mass /volume
Measures the mass to charge ration of ions
mass spec
D/P cell
measures change in pressure using two sensors
A cascade control is typically used to:
minimize the effects of secondary variable disturbances based on the primary PV
Proportional control is defined as a control:
mode in which the controller produces a direct signal that is proportional to the controlled variables percentage of deviation from the set point
Pressure increases when
molecules begin to move faster
The ______________ is a device or group of devices that dictates the performance of an electric motor
motor control center
multi-variable control
multiple inputs/outputs affect multiple controlled variables; often requires computerized management
A _____ device is used to detect the point where gamma radiation is shadowed by the tank level
nuclear
Proportional Action / Gain
output is proportional to the deviation from setpoint, May overcorrect/undercorrect
set of conditions designed to ensure safe operation that must be met before a piece of equipment can be turned on
permissive
A unit of measure which describes the degree of acidity or alkalinity of a solution
ph
Measurement of hydrogen ion concentration
ph
The standard reference material used in resistance temperature detectors is:
platinum
P/I conversion-
pneumatic to current
_____ level measurement is measured at one distinct point in a tank.
point
A _____ _____ flow meter measure volumetric flow rate of a liquid or gas by separating the flow streams into known volumes and counting then over time
positive displacement
which unit of measurement is commonly associated with a mass flow rate?
pounds per hour
Some type of regulator is used in instrumentation pneumatic systems to control what parameter?
pressure
A bourdon tube is normally found inside a:
pressure gauge
A pneumatic signal simulator can be used to calibrate:
pressure switches
A particular machine has been determined to be unsafe to operate. Danger tags and locks should be used to:
prevent the operation of the machine
ratio control
primary controller establishes setpoint for secondary controller, in order to maintain a set ratio between the two flow rates
cascade control
primary controller establishes the setpoint in the secondary controller , in order to meet the primary setpoint
If a control valve is controlling on and off the seat, it usually means the:
process is over powering the spring in the valve
A set of rules that govern the transmission and makeup of binary data
protocol
To reset a tripped breaker:
pull the breaker handle down then up
a measurement of the properties of a substance
qualitive
a measurement of the amount of properties within a substance
quantitative
AC voltage becomes DC voltage as it passes through the ___________.
rectifier
design feature that provides more than one function for accomplishing a given task so the failure of one function does not impair the system s ability to operate
redundancy
A PLC ____ is a storage area within the PLC.
register
In a pilot operated regulator, the pilot is the controlling device of the main:
regulator
A relay changes the position of its switch contacts from shelf state when the:
relay coil is energized
"if a fixed amount of mass occupies a larger volume, the head pressure will _____"
remain the same
A control valve that is labeled "air to open" is one that:
requires air pressure to open the valve
A temperature-measuring device that operates on the principle that electrical resistance changes with temperature is a:
resistance thermal device
The temperature coefficient of resistance for an RTD defines the [x] to [y] relationship
resistance/ temperature
Common use for vibration switch-
rotating equipment; compressor, centrifuges, steam turbines, blowers.
"____ is the time it takes to check input status, execute the program, and update output status."
scan time
Which tools are regularly used when troubleshooting an instrument?
slotted and Phillips head screw drivers adjustable wrench multimeter to test electrical side of loop pressure and/or temperature testing gauges two-way radio
Translate all items into PLC understood symbols
step 1
All devices are to be given addresses
step 2
Conversion to logical sequence of events
step 3
Capillary tubing with a bulb on the end is normally used on instruments that provide:
temperature readings
"Full testing, which is often done during the initial commissioning or following a turnaround, involves the application of a specific value to the instruments to initiate a shutdown"
true
"Some accessory devices connected to the data highway include printers, recorders, data loggers etc."
true
"in laminar flow, velocity, pressure, and other flow properties at each point in the fluid remain constant."
true
"the mass flow meters eliminate the need for compensation due to temperature, pressure, density."
true
feedback control loop
the controller responds to a shift in the process variable (creating an error when its different from the setpoint) by manipulation the process to return to the setpoint.
E/P conversion-
the conversion of a signal from voltage to pneumatic."
innage
the measurement from the bottom of a tank to the surface of a material
Ullage
the measurement from the surface of a material to the top of a tank
indirect measurement
the measurement of another property of a contained material to determine level
Interface level
the measurement of the point where two immiscible materials meet
Direct measurement
the measurement of the process variable (level)
All of the following are reasons to install heat tracing EXCEPT to control:
the sublimination point
A gradual change could be an indication of an aging thermocouple
true
A mass spectrometer is often used with a gas chromatograph to identify different substances within a test sample
true
A sticking control valve can cause instability in a loop
true
AC is used with high voltage power lines because it can be stepped up or down to meet the voltage requirements
true
For a DCS node, al ocal controller processes information and sends out control commands
true
For a DCS node, digital signals are sent to the computer with MUX
true
If all AND gate inputs are true, the output will be:
true
Observation will aid in remote troubleshooting.
true
Resistivity is the opposite of conductivity
true
15
thermal expansion of a filling fluid due to ambient or process temperature changes has minimal effects on accuracy when the measurement range is _______ PSIG or more.
Two dissimilar metals joined together which when heated will generate a small voltage
thermocouple
All of the following are true about direct process recorders EXCEPT:
they are normally used in a control center
Sensors are used to help detect the interlock conditions
true
Switchgears are located anywhere that isolation and protection may be required
true
The control loop sends signals to the individual node to process
true
The subdivided nodes communicate with the host node.
true
turbulent flow has a uniform velocity profile
true
The ______________ insures clean and uninterrupted power to instrumentation.
uninterrupted power supply
backup power unit that provides continuous auxiliary power
uninterrupted power supply
2oo3
used in voting logic to initiate shutdown
sensor
used to detect interlock conditions
ESD
used to shutdown equipment if shutdown condition occurs
On a control valve, the packing follower compresses the packing rings around the:
valve stem
In a normal DP cell calibration, the low-pressure side is:
vented to atmosphere
analyzes the signals from several devices, all of which are monitoring the same condition
voting logic
a _____ _____ drilled next to the metering hole allows liquids or gasses to pass that would otherwise affect the accuracy of the meter
weep hole
Each symbol or instruction in a PLC has a unique address.
True
Insulation-
'protective covering place around steam and electrical tracing tubes to prevent heat loss and to protect personnel."
Gain
(change in output span)/(change in input span) answer in %
The temperature range of a transmitter is 0 to 200 degrees F. The output signal range is 3 to 15 psig. What would be the expected output output signal for an input temperature of 150 degrees F?
12.00 psig
distributed control system
A P&ID can show only part of the control strategy implemented in a ______ ______ ______ or a programmable logic controller.
A
A P&ID uses the letter ____ as a modifier representing an alarm in an instrument tag balloon.
I
A P&ID uses the letter ____ for electrical current in an instrument tag balloon.
F
A P&ID uses the letter ____ for water flow in an instrument tag balloon.
tape float
A _____ _____ is a continuous level measuring instrument consisting of a floating object connected by a chain, rope, or wire to a counterweight, which is the level pointer.
thermal imager
A _____ ______ is an infrared device that uses a two-dimensional array of IR detectors to generate a thermal image.
bubbler
A _____ is a level measuring instrument consisting of a tube extending to the bottom of a vessel; a pressure gauge, single-leg manometer, transmitter, or recorder; a flow meter to adjust the flow rate of air or nitrogen through the tube; and a pressure regulator to limit the inlet pressure.
thermopile
A _____ is an electrical thermometer consisting of several thermocouples connected in series to provide a higher voltage output.
none of these
A _____ pressure cell is a transducer that converts a differential pressure to an output signal.
set point
A ______ ______ is the desired value at which the process should be controlled.
reflex
A ______ gauge glass is designed to improve visibility of liquid in the glass by reflecting light with saw-tooth surfaces that act as prisms.
displacer
A ______ is a liquid level measuring instrument consisting of a buoyant cylindrical object that is heavier than the liquid it is immersed in and is connected to a spring or torsion device that measures the buoyancy of the cylinder.
micro bath
A ______ is a small tank containing a stirred liquid used to calibrate thermometers.
pyrometer
A ______ is a temperature-measuring instrument that is used to measure temperatures beyond the range of a mercury thermometer.
time domain reflectometer
A ______ is another name for guided wave radar.
fluid
A ______ is any material that tends to flow.
capacitance
A ______ pressure transducer is a diaphragm pressure sensor with a capacitor as the electrical element.
balloon
A _______ is a circular symbol used to identify the purpose of an instrument or device.
manometer
A _______ is a device consisting of a liquid-filled tube used for measuring pressure.
barometer
A _______ is a manometer used to measure atmospheric pressure.
conductivity probe
A _______ is a point level measuring system consisting of a circuit of two or more probes or electrodes, or an electrode and the vessel wall where the material in the vessel completes the circuit as the level rises in the vessel.
glass tube
A _______ is a secondary chamber fitted into a metal tube chamber.
blackbody
A _______ is an ideal body that completely absorbs all radiant energy of any wavelength falling on it and reflects none of this energy from the surface.
probe
A _______ is an insertable device that contains a sensor.
calorie
A _______ is the amount of energy necessary to change the temperature of 1 gram of water by 1 degree Celsius from 14.5 degrees Celsius to 15.5 degrees Celsius.
load cell simulator
A _______ provides a signal that simulates the signal from load cells at various weights.
pulsed radar level
A _______ sensor is a level measuring sensor consisting of a radar generator that directs an intermittent pulse with a constant frequency toward the surface of the material in a vessel.
closed
A ________ control loop is a control scheme in which the value or status of the control variable is continually evaluated by the controller and adjustments made based on the evaluation.
gas-filled pressure-spring
A ________ thermometer is a pressure-spring thermometer that measure the increase in pressure of a confined (kept at constant volume) gas due to a temperature increase.
electronics module, waveguide, and a float containing a magnet
A magnetostrictive sensor is a part of a continuous level measuring system consisting of a ____________.
True
A smart transmitter contains an A/D converter
27.7
A pressure of 1 PSI is equal to a hydrostatic head of ____ inches of water.
helical, spiral, or C shape
A pressure spring is a mechanical pressure sensor consisting of a hollow tube formed into a ______ shape.
Feedforward
A reactor's catalyst feed is manipulated due to a predicted load change
True
A signal can be considered output or input but never both
electronic calibrator
A standard temperature transmitter can be calibrated by removing the input wires and replacing them with an ________.
When considering PLCs, a "gate" refers to
A symbol indicating a open/closed circuit
Feedback
A tank level is manipulated because an error signal has developed
averaging thermocouple
A(n) _____ is an electrical thermometer consisting of a set of parallel-connected thermocouples that is commonly used to measure an average temperature of an object or area.
closed loop
A(n) __________ is a control system that provides feedback to the controller on the state of the process variable.
Name four I/O modules usually found in the architecture of a DCS system
A/I analog input A/O analog output D/I digital input D/O digital output
Name the four I/O modules usually found in the architecture of DCS system
A/I analog input, A/O analog output, D/I digital input, D/O digital output
False
Capacitance is the ratio of the insulating ability of a material to the insulating ability of a vacuum.
increase
Adding enough inlet tubing to allow the process fluid to cool before entering the sensor may _____ the useful temperature range of pressure sensors.
Heat Tracing
Adding heat to process piping or equipment to keep process fluids at constant temperature (or keep it from freezing) usually done with electrical heat tape, steam tracing, glycol tracing, or other hot utility oil. Note: that the placement of heat tracing around a process pipe is important is there is heat tracing along the bottom of a pipe, where water can build up, it can increase the corrosive action of the water in the pipe.
absolute
Adding the letter "a" after a unit of pressure, as in PSIA, indicates _______ pressure.
A disadvantage of an analog signal is that it is ______.
Affected by noise
What do the letters AC on a control valve drawn on a loop diagram mean?
Air to close
Performing visual inspection to verify mechanical installation of loop components includes:
All components including process connection, primary elements, control elements, and wiring
bimetallic
Alloys that have closely controlled coefficients of thermal expansion make a _______ thermometer a very dependable temperature-measuring device.
Proportional Gain
Amount of deviation of the controlled variable from the set point required to move the controller output through its entire range, expressed as a % of span.
incline manometers have higher resolution over the desired span
An incline manometer has the advantage over a standard U-tube manometer because:
coil
An inductive probe is a point level measuring instrument consisting of a sealed probe containing a _______.
Local
An instrument located near the process.
Pneumatic
An instrument powered by air or other gasses.
A(n) __?__ measurement and/or signal represents a range of values.
Analog
Typical signals used in process control are __?__, __?__, and __?__.
Analog Discrete Digital
For an analog pneumatic transmitter to communicate with a digital controller the signal must be converted first to an
Analog electrical signal
True
Analog systems more closely reflect real world processes than the digital systems
Which of the following must be determined before selecting a pressure-reducing regulator?
Capacity required
industrial
Common thermal expansion instruments are ______ thermometers.
Transducer
Designed to convert an electric signal to a pneumatic signal - referred to a I to P.
The ____ performs all the logic and math operations of the PLC.
CPU
Which wiring diagram does NOT show discrete conductors from end to end, but in a bundle?
Cable DIagram
"Proving" a loop involves:
Calibration of transmitters controllers and final control elements
The key advantage of digital instrumentation over analog is that digital
Can be read by computers
Controller
Designed to compare a signal with a set point and transmit a signal to a final control element
Transmitter
Designed to convert a measurement into a signal - this signal will be transmitted to another instrument
The multi - Luke computer - controlled system presently used to manage process technology is called
DCS
The position of the relay contacts and switches are shown in what state on schematic diagrams?
De-energized or shelf
Which device is the MOST accurate for performing pneumatic simulation?
Dead weight tester
Multiple signals from field instruments would be forwarded to a controller by a
Demultiplexers
What are the standard signal ranges (LRV to URV) for the following signal types?
Electrical, analog, mA: 4-20 mA Pneumatic, psig, 3-15 psig
Grounding
Establishing a conductive connection to divert harmful/stray electric currents to the earth or another ground source. Grounding is usually connected to process vessels, piping systems, and equipment. Grounding systems may have to be coordinated with other electrical protection systems, such as cathodic protection (for corrosion) for buried piping and equipment that is mounted on the ground.
Feedback Control
Example: A tank level is manipulated because an error signal has developed. The system is responding to a change in the process value-an 'error' Error=PV-SP The changed PV is fed back to the control loop to determine whether further adjustment is needed.
"In ladder logic, a circuit path will be complete only if all the contacts are in an open state."
False
"When level increases, the vessel bottom pressure decreases"
False
"a thermowell is a device that measures resistance to infer temperature, but has a resistance change 10 times greater than that of a 100 ohm platinum RTD"
False
"examples of indirect measurements include sight glass, dip stick, and float"
False
"when temperature increases, pressure decreases in a closed vessel"
False
A PLC does not understand ladder logic; it only understands schematic diagrams.
False
A PLC will energize an output when only one condition on the rung is true
False
A digital signal is any variable signal continuous in both time and amplitude
False
A process instrument will be categorized into only one of the following categories, location, function, or power source.
False
A thermistor is a protective device used to isolate the temperature sensing element from process
False
Accumulating or retentive times need only one input
False
An analog signal is a discrete-time signal that takes on only a discrete set of values
False
Atmospheric pressure is the same regardless of the measurement point on the earth
False
Digital controller require more care and bumpless transfer from manual to automatic
False
Digital instruments showed change in a continuous manner
False
For a digital control to activate an analog valve only one single conversion will ever be necessary
False
Human offer improved reliability, stamina, and speed when compared to instrumentation.
False
It is important for the temperature sensor to be in contact with the bottom of a thermowell for slower heat transfer
False
Measuring one process variable to infer another is an example of direct measurement
False
Measuring the actual process variable directly is an example of indirect measurement
False
One disadvantage of PLCs is that system documentation has become more difficult
False
PLCs are limited to On / Off control.
False
PSIG = PSIA = 14.7
False
The initiating controller and A cascade Loop is called the secondary controller
False
The ladder logic is scanned right to left and top to bottom.
False
Thermocouples are more accurate than RTDs
False
What BEST determines the required torque for bolt tensioning?
Grade of bolt
cascade
In the process flow diagram, the control system represented by LIC-14 and FIC-25 represents a _______ control loop.
Ladder diagrams generally show contacts and relays
In their normal position
When tuning a controller, increasing gain:
Increases sensitivity
Reverse Action
Increasing Input=Decreasing Output
Direct Action
Increasing Input=Increasing Output
A non-contact temperature sensing method detects:
Infared radiation
blackbody
Infrared radiation thermometers are calibrated with a ______ calibrator.
faster
Infrared radiation thermometers generally have _______ response times than thermal expansion thermometers.
Microprocessor systems of today can contain a wide variety of user-defined algorithms which __?__ and __?__ the process.
Initiate Control
All control systems share a common thread which are the __?__ and __?__ control elements.
Initiating Final
I/) are identified as __?__ and __?__ when defining control signals.
Input Output
Field instruments are usually connected to some type of _______or ______device that resides on an input/output a highway
Input/output
optical isolator
Many transmitters include an _______ to eliminate an electrical path for ground currents and other electrical noise.
Density is _____ per unit _____
Mass/ Volume
Why is the selection of construction materials for the instrument installation an important part of maintaining signal integrity?
Materials of construction may be conductive, or have resistive properties of their own. In addition, materials of construction affect the corrosion in a system. Materials must be chosen to properly conduct signals without interference, and to be reliable over long-term use.
Manometer
Measures pressure with liquid filled tube
A DCS system divides production control in a plant into several subparts called
Nodes
Which of the following materials is selected when resistance to corrosion or high temperatures is required?
Nonferrous alloy
This type of control is used in places were a fairly large measurement zone is not a problem
On/off
The control system of an air conditioner in a typical residential home is an example of a(n)
On/off control
Split-Range Control
One controller operates two final control elements. Each FCE flow controller element responds to a different portion of the controller output signal range.
False
One disadvantage of PLCs is that system documentation has become more difficult
Split Range
One final control element (Valve A) responds to the lower half of the output signal while another (Valve B) responds to the upper half of the out put signal
resistance
Opposition to the flow of electrons is called ________.
_____ is the pressure scale that begins at theoretical zero pressure and increases from there.
PSIA
_____ is the pressure scale that begins at atmospheric pressure and increases from there.
PSIG
Which of the following tools should be used to remove old packing from the packing gland?
Packing extractor
pressure pulsations, high temperatures, and corrosive materials
Pressure gauges must be protected from ______.
Ratio Control
Primary controller establishes set point for secondary controller, in order to maintain a set ratio between the two flow rates.
Cascade Control
Primary controller establishes the set point in secondary controller, in order to meet the primary set point.
What part of a loop or an instrument first senses the value of a process variable, such as the level of liquid in a tank or the temperature of product?
Primary element
Measurement device
Primary elements and sensors
Uses a change in the resistance of a wire to indicate temperature change
RTD
_____ is the transfer of heat through emitting radiant energy in the form of waves or particles.
Radiation
Hunting
Random behavior or cycling above and /or below the setpoin. Caused by improper design, installation, calibration, or tuning or the controller.
Which absolute temperature scale(s) contain(s) 180 degrees between the freezing point of water and the boiling point of water?
Rankin
Control involving one uncontrolled and (wild) Stream and one controlled stream
Ratio
For all processes, the signals used to __?__, __?__, and __?__ are all performed by devices that provide and interface from a controller to working process.
Record Monitor Control
Cascaded control schemes are used to
Reduce lag time and better control
The _______ feature of a DCS system makes it extremely reliable
Redundant
Control system today are used to __?__ a process or indicate when a process has reached a desired __?__
Regulate Set point
PLCs now handle functions formally performed by
Relays and drum switches
List for reasons a DCS systems is preferred over an analog base system
Reliability and accuracy, cost effectiveness, speed, space efficiency
Remote Manual Control
Setting the controller to open or close a valve out in the processing area from a control room
Windup
Saturation of the controller output signal to its minimum or maximum value if the process variable does not return to the set point.
temperature, flow, pressure, level
Select the four process variables.
An operating system depends upon the accurate __?__, __?__, and __?__ of data that is the responsibility of the field devices and therefore, the responsibility of the field technician.
Sensing Signaling Transmission
The desired value where the process should be maintained is called the __?__
Set point
Spanning
Setting or calibrating the LRV/URV of a device, or checking system response throughout the calibrated or operational range.
Redundant
The ___ feature of a DCS system makes it extremely reliable
heat capacity
The _____ _____ of a material is the amount of energy needed to change the temperature of the material by a certain amount.
cold junction
The _____ ______ is the end of a thermocouple that is kept at a constant temperature in order to provide a reference point.
hot junction
The _____ ______ is the joined end of the thermocouple that is exposed to the process where the temperature measurement is desired.
specific heat
The _______ of a liquid is the ratio of the heat capacity of that liquid to the heat capacity of water at the same temperature.
dielectric constant
The _______ of a material determines the degree of absorption and, therefore, the strength of a reflected radar wave.
Bumpless Transfer
The act of changing the controller from manual to automatic or vice versa without a significant change in the controller output is called...
Local Manual Control
The act of controlling a process variable by hand within the processing area
reference
The actual temperature of a dry well block or micro bath is measured with a ________ thermometer.
dielectric constant, the surface area of the conductors, and the distance between the conductors
The amount of capacitance depends on the ________.
voltage
The amount of heat energy to which a thermocouple is exposed causes the ______ generated to vary so the new value can be interpreted by the electronic circuits of a transmitter and indicated as degrees.
Process Equilibrium
The condition that exists when there is a balance of material and energy within a system or process. Also known as 'steady state'.
valve
The final element is most often which of these?
True
The increased reliability provided by PLCs make up for the increased wiring required
False
The initiating controller in a cascade loop is called the secondary controller
Can Be Read By Computers
The key advantage of digital instrumentation over analog is that...
temperature indicating controller
The letters T I C on a controller symbol on a P&ID stand for ________ ________ _______.
temperature switch high
The letters T S H on a P&ID represent _____ _____ _____.
temperature valve
The letters T V on a P&ID represent ______.
On-Off Control
The liquid in this tank is emptied once it reaches a specific level. Triggered by some kind of switch. Operation is not modulated-Just full on or full off.
True
The local computers for each node in a DCS system communicate with a host computer
senses the condition of the process variable
The primary element of a control loop:
distance:size
The ratio ________ is often used to describe optical resolution.
Over-Range
The signal value of a device or system exceeds the maximum allowable value.
light in air
The speed of a radar signal is equal to the speed of _______.
faster than
The temperature response time when measuring a liquid with a thermal expansion thermometer is _____ when measuring a gas.
conduction
The transfer of heat energy that occurs when molecules in a material are heated and heat is passed from molecule to molecule is:
On/Off
This type of control is used in places where a fairly large measurement zone is not a problem
Override
This type of control prevents the constrained variable from exceeding its limit
low level
Thermocouple break protection is a circuit where an electronic device sends _____ current across the thermocouple.
Uses a capillary tube filled with a liquid which responds to temperature change.
Thermometer
Lead/Lag
This type of circuit is used to swap the lead role between two equal parallel components, such as compressors and/or evaporators in a refrigerator system
Which is not a function of an instrument?
Transcending
Steady State
Trend condition in which the process is in equilibrium and running smoothly, producing a relatively straight-line output.
" examples of indirect measurements include head pressure, displace, and load cells"
True
"When temperature decreases, volume decreases"
True
"at sea level, atmospheric pressure is 14.7 PSIA"
True
"for a 1000- ohm platinum RTD, the expected resistance at 0C is 1000"
True
"head pressure measurements are affected by changes: density, specific gravity, speed/temperature"
True
"when boiling point decreases,pressure decreases"
True
"when temperature increases, density increases"
True
"when wiring a thermocouple to a remote PLC, it is important to use extension wire made from the same material that comprise the thermocouple"
True
A change in one variable in a process can produce a dramatic change in another measurement variable.
True
A signal can be considered output or input but never both
True
A smart transmitter contains and A/D converter
True
A thermometer is a local instrument used to determine the temperature of a substance
True
A/D Converter A device that converts an analog signal to digital signal
True
Analog systems more closely reflect real world processes then the digital systems
True
Atmospheric pressure changes with elevation.
True
Convert 10 in. Hg into in. of water: (10 in. Hg/ 2.04 in. Hg) * 27.7 in. H2O = 135.8 in H2O
True
D/A Converter A device that converts a digital signal to analog signal
True
bridging
Which of the following is a condition arising in a silo when material has built up over the feeder, blocking all flow out of the silo?
Hazards from Aerosol cans include all of the following EXCEPT:
implosion due to sudden gas release
What cases might vibration detector be placed relative to the casing-
in machines such as turbines, centrifugal pumps, and compressors. This is because of the weight and rigidity of the casing, vibration in the moving rotor may not be felt on the frame of the machine, so vibration detectors do better to directly measure shaft vibration relative to the casing to indicate when a seal and bearing clearances are in danger."
split-range control
one controller operates two final control elemnts. each FCE responds to a different portion of the controller ouput signal range
A/an ____ can be thought of as a window to the process. The main function of a work station is to allow the operator to control the process.
operator station
-"measurement that uses reflection, refraction or absorption properties of light to measure the chemical or physical properties of a solution"
optical
Special flanges to mount a metal plate flow element are called _____ _____
orifice flange
A/An ____ _____ is a piece of metal with a precise hole drilled thought and is used to create a pressure drop in a flowing process
orifice plate
With a smaller integral time, the output of a PID controller will be:
smaller
The "adjustable range" of a pressure switch refers to the:
span of pressure within which the sensing element can be set to actuate the contacts of the switch
Measures variations in the transmittance of light through a sample
spectrometer
Flow rate is proportional to the ____ _____ of differential pressure
square root
If the diaphragm in a pressure transmitter becomes severely coated, a sensor may register:
zero reading
