Domain 2 Flashcards
- A Coriolis flowmeter is ranged 0 to 100 lbs/hr (0-45.36 kg/hr) and has an output of 14 mA. What is the process variable reading?
A. 6.25 lbs/hr (2.83 kg/hr)
B. 62.5 lbs/hr (28.3 kg/hr)
C. 8.75 lbs/hr (3.97 kg/hr)
D. 87.5 lbs/hr (39.7 kg/hr)
B. 62.5 lbs/hr (28.3 kg/hr)
- A megohmmeter is used to measure which of the following?
A. Conductor resistance
B. Conductor voltage
C. Insulation voltage
D. Insulation resistance
D. Insulation resistance
- When performing a calibration check, you find it a 4-20 mA output linear transmitter has a reading of 8.05 mA at 25% input, what is the full-scale error?
A. .313%
B. 31.2%
C. .05%
D. 5%
A. .313%
- A diamond on instrumentation diagram encloses information about:
A. Calibration
B. The set point
C. Controller action
D. The power source
B. The set point
- Central connection points for signal lines are called:
A. Instrument ports
B. Junction boxes
C. Input/output junctions
D. Field ports
B. Junction boxes
- In the following diagram, what is the proper range to set up the transmitter if the low side is a wet leg? (see photo)
A. LRV = -280 InH2O (711.2 cmH2O), URV = 0 InH2O (0 cmH2O)
B. LRV = -324 InH2O (823 cmH2O), URV = -12 InH2O (30.5 cmH2O)
C. LRV = 0 InH2O (0 cmH2O), URV = 280 InH2O (711.2 cmH2O)
D. LRV = 0 InH2O (711.2 cmH2O), URV = 336 InH2O (853.4 cmH2O)
B. LRV = -324 InH2O (823 cmH2O), URV = -12 InH2O (30.5 cmH2O)
- In an electronic loop diagram, junction box connections are represented by:
A. Circles
B. Diamonds
C. Ellipses
D. Squares
D. Squares
- Some flange mounted devices cannot be valved out of process piping. In such cases isolation from dangerous process materials and pressures is obtained by a metal disc known as a:
A. Blank
B. Plate
C. Stop
D. Blind
D. Blind
- The thermostat for a central air conditioning system is set at 68°F. This value is an example of the:
A. Manipulated variable
B. Deviation
C. Set point
D. Controlled variable
C. Set point
- To convert the output from a thermocouple to a standard 4-20 mA instrument signal, a(n) ___________ with cold junction compensation would be used.
A. I/P transducer
B. P/I transducer
C. D/A converter
D. mV/I transducer
D. mV/I transducer
- Iron constantan thermocouples are designated by the letter:
A. T
B. J
C. B
D. S
B. J
- To change the 4 to 20 mA analog signal from a transmitter to the signal required by a digital controller, a(n) ____________ must be part of the instrument signal loop.
A. I/P transducer
B. Signal conditioner
C. D/P transmitter
D. A/D converter
D. A/D converter
- A device that changes a voltage signal to a current signal is normally referred to as a(n):
A. P/I transducer
B. E/I transducer
C. D/P transmitter
D. V/C converter
B. E/I transducer
- A pneumatic control valve, without a positioner, is the final control element in an instrument loop. The transmitter and controller are both electronic. In order for this control system to operate, a(n) _________ must be installed in the instrument signal line between the controller and the control valve.
A. I/P transducer
B. mV/I transducer
C. D/A converter
D. P/I transducer
A. I/P transducer
- The transmission signals considered standard for most instrument systems are:
A. 4 to 20 PSI and 3 to 15 mA
B. 0 to 24 V and 0 to 20 PSI
C. 3 to15 PSI AND 4 to 20 mA
D. 0 to 20 mA and 0 to 15 psi
C. 3 to 15 psi and 4 to 20 mA
- In most process control systems the final control element is a:
A. Transmitter
B. Sensor
C. Controller
D. Valve
D. Valve
- A control valve with a direct acting actuator with springs and is air to close will:
A. Fail closed
B. Maintain position
C. Fail open
D. Fail indeterminate
C. Fail open
- A pneumatic valve actuator that operates over an instrument signal range of 9 to 15 psi is referred to as:
A. Split range
B. Failsafe
C. Air to close
D. Full range
A. Split range
- RTD is short for:
A. Reactive tuning deviation
B. Resistance temperature detector
C. Resistance tone dampening
D. Resonant temperature device
B. Resistance temperature detector
- What is the device that changes a voltage signal to a current signal?
A. P/I transducer
B. E/I transducer
C. D/P transmitter
D. V/C converter
B. E/I transducer
- While increasing the pressure during a performance test, if you overshoot the specified test point by small margin, you should:
A. Take the reading at the pressure you have reached
B. Reduce pressure gradually to the test point value
C. Reduce pressure to zero and start again
D. Reduce pressure to below the test point increase it again until the test point is reached
D. Reduce pressure to below the test point and increase it again until the test point is reached
- In this “bubbler” level control application, FI-1:
A. Sets LIC-set point
B. Controls purge gas flow
C. Controls gas pressure
D. Indicates purge gas flow
D. Indicates purge gas flow
- Which of the following types of actuators responds to a pneumatic signal?
A. Solenoid
B. Motor
C. Diaphragm
D. Electromagnetic valve
C. Diaphragm
- Changing the point of origin for input data, and the output signal destination is easy with the distributed control system because many changes can be implemented by:
A. Relocating wire jumpers in a junction box
B. Changing the pneumatic tubing connections
C. Reassigning inputs/outputs by changing loop configuration
D. Installing new transmitters and final control elements
C. Reassigning inputs/outputs by changing loop configuration
- What is a thermowell?
A. Protective tube
B. Type of manometer
C. Expandable bulb
D. Reservoir
A. Protective tube
- The body of a valve may contain packing material that prevents leakage:
A. Along the valve stem
B. Between the seat and the disc
C. Between the bonnet and the body
D. Between the inlet and outlet ports of the valve
A. Along the valve stem
- Which type of flowmeter does a rotor mounted axially within a pipe between a set of bearings describe?
A. Magnetic
B. Turbine
C. Water meter
D. Venturi tube
B. Turbine
- Which type of flowmeter measures flow by measuring volume directly?
A. Coriolis
B. Magnetic
C. Positive displacement
D. Differential pressure
C. Positive displacement
- What occurs if the temperature of the thermocouple measuring junction is lower than the reference junction?
A. There is no EMF output
B. The output voltage polarity is reversed
C. The polarity stays the same but voltage increases
D. The EMF remains the same when temperature changes
B. The output voltage polarity is reversed
- A ground loop on shielded cable can be avoided by:
A. Attaching a safety ground to the instrument casing
B. Grounding the shield at only one end of the circuit
C. Attaching a safety ground to the control panel
D. Grounding the shield of both ends of the cable
B. Grounding the shield at only one end of the circuit
- A meter reading of 1 ohm between an ungrounded signal lead and the earth ground indicates a problem of:
A. A lead having an unwanted connection to ground
B. An open circuit from the lead to ground
C. An open circuit from the lead to the casing
D. None of the above
A. A lead having an unwanted connection to ground
- What kind of wires in a process control loop would most likely be shielded cables?
A. Power wires
B. Ground wires
C. Signal wires
D. Control wires
C. Signal wires
- A device used to change an analog signal to a digital signal is most often called a:
A. Transducer
B. Signal conditioner
C. Transmitter
D. Converter
D. Converter
- A 4 to 20 mA electronic transmitter has an input range of 50 to 330°F. If the output is 13.77 mA what is the indicated temperature in degrees Fahrenheit?
A. 173
B. 221
C. 266
D. 302
B. 221
- If the range of 3 to 15 psi pneumatic transmitter is 50 to 350°F, what is the output signal value, in psi, at 198°F?
A. 5.7
B. 7.2
C. 8.9
D. 12.6
C. 8.9
- When the percentage of flow through a valve equals the percentage of plug movement, a valve has:
A. Linear flow characteristic
B. Equal percentage flow characteristic
C. Quick opening flow characteristic
D. Curved flow characteristic
A. Linear flow characteristic
- Which of the following parts of the globe valve serves the same purpose as the disc in a butterfly valve?
A. Seat
B. Plug
C. Packing rings
D. Packing flange
B. Plug
- The process of grinding the plug and seat of a valve is called:
A. Characterizing
B. Linearizing
C. Lapping
D. Calibrating
C. Lapping
- The dead band of an instrument is:
A. The band that prevents the instrument from being tampered with by unauthorized persons
B. The range of values for which the instrument gives inaccurate readings
C. The size of the instrument indicated by the divisions on the scale of the instrument
D. The range that an output signal may be changed on reversal of direction without an observable change in the output
D. The range that an input signal may be changed on reversal of direction without an observable change in the output
- A continuity check is used to check for opens or shorts and should be made prior to hook-up of the field transmitter to the control room so that the technician:
A. Can assure that the transmitter is being hooked up to the proper indicator or controller
B. Can make sure that the proper voltages are present
C. Can make sure that he continue hook up on a particular transmitter
D. Knows that he may connect another transmitter to the loop circuit
A. Can assure that the transmitter is being hooked up to the proper indicator or controller
- Impulse lines are used with:
A. Pressure meters
B. Magnetic flowmeters
C. Positive displacement meters
D. Open channel meters
A. Pressure meters
- Which meter does not use an obstruction?
A. Head meter
B. Magnetic meter
C. Open channel meter
D. Turbine meter
B. Magnetic meter
- The Coriolis effect is associated with the:
A. Head meter
B. Mass flow meter
C. Positive displacement meter
D. Turbine meter
B. Mass flow meter
- A beveled orifice should form an angle of:
A. Not less than 30° to the axis of the pipe
B. Not more than 30° to the axis of the pipe
C. Not less than 45° to the axis of the pipe
D. Not more than 45° to the axis of the pipe
C. Not less than 45° to the axis of the pipe
- Which orifice plate is used to eliminate damming of material at the top or bottom of the pipe?
A. Concentric
B. Round edged
C. Quadrant edged
D. Segmental
D. Segmental
- The most common pressure tap is the:
A. Corner
B. Flange
C. Pipe
D. Vena contracta
B. Flange
- One of the most important considerations of the installation of an electromagnetic flow meter is:
A. The Reynolds number of the fluid
B. The use of a straightening vane
C. Bonding the flowmeter to the piping
D. Observing the correct polarity
C. Bonding the flowmeter to the piping
- Control valves which have a plug position by a stem which slides through a packing gland are often referred to as:
A. Rotary motion control valves
B. Linear motion control valves
C. Ball control valves
D. Motorized control valves
B. Linear motion control valves
- The control valve that produces an inherent equal percentage increase, or decrease, over the existing flow when the plug is repositioned has a(n) __________ characteristic under constant pressure drop conditions.
A. Modified parabolic
B. Equal percentage
C. Linear
D. Quick opening
B. Equal percentage
- If a control valve will pass 25% of its full capacity when 25% open, 50% of its capacity when 50% open, and 75% when 75% open, the inherent characteristic is:
A. Quick opening
B. Equal percentage
C. Throttling
D. Linear
D. Linear
- If the pressure drop (delta P) across a valve increases, without a change in valve position, the flow of fluid through the valve will normally:
A. Decrease
B. Increase
C. Remain the same
D. Change direction
B. Increase
- A piston actuator:
A. Seldom has a pneumatic positioner
B. Can only be actuated by hydraulic pressure above 100 psig
C. Cannot be made failsafe without electric limit switches
D. Can be used if a long stroke or high actuator pressure is required
D. Can be used if a long stroke or high actuator pressure is required
- An instrument calibration error is reported. Your analysis of the calibration plot below determines that __________, and the instrument does, in fact, need recalibration.
A. There is a zero error
B. There is a span error
C. There is both a zero and the span
D. There is a linearity error
B. There is a span error
- Which of the following is not necessary when zeroing or calibrating a magnetic flowmeter?
A calibration factor for the flow tube assembly
B. Flow tube full of process material
C. Proper grounding
D. Warm-up period for the fluid in the system
D. Warm-up for the fluid in the system
- A DP cell is mounted 3 feet below the zero level in an open tank. For a true level reading, the transmitter output must be:
A. Calibrated for elevated zero
B. Calibrated for span
C. Calibrated for true zero
D. Calibrated for suppressed zero
D. Calibrated for suppressed zero
- The standard range for pneumatically transmitted signals is:
A. 3 to 15 psig
B. 5 to 20 psig
C. 1 to 10 psig
D. 4 to 20 psig
A. 3 to 15 psig
- Approximately what is the pressure, in PSI, at the bottom of a 20 foot tank filled to 100% capacity with fluid that has a specific gravity of 1.5?
A. 8.7
B. 12.99
C. 5
D. 35
B. 12.99
- A process variable which is to be maintained at some desired value (temperature, pressure, level, flow) by means of manipulating another process variable, is the:
A. Manipulated variable
B. Measured variable
C. Controlled variable
D. Disturbance variable
C. Controlled variable
- A plant has a water tank mounted on top of an 80 foot platform. The tank is 30 feet high. What is the level of water in the tank if the differential pressure transmitter mounted on the bottom of the tank reads 277 inches of water?
A. 10 feet
B. 17 feet
C. 23 feet
D. 30 feet
C. 23 feet
- The pressure at the bottom of a 20 foot tank completely filled with fluid that has a specific gravity of 1.75 will be:
A. 11.428 psi
B. 15.15 psi
C. 21.75 PSI
D. 35 psi
B. 15.15 psi
- Pneumatic actuators:
A. Cannot be used in hazardous or high humidity atmospheres
B. Can be made failsafe
C. Do not have sufficient speed or power for most applications
D. Are too complicated and unreliable for many applications
B. Can be made failsafe
- A hollow metal cylinder which guides the movement of the plug and holds the seat ring in place is found in a:
A. Seat
B. Butterfly valve
C. Cage guided valve
D. Ball
C. Cage guided valve
- The term valve “trim” refers to the:
A. Pneumatic actuator
B. Stem, plug, and seat ring
C. Orientation in a process installation
D. Body style and material of construction
B. Stem, plug, and seat ring
- In a bubbler level measuring system with the open end of the purge pipe at the bottom of the tank, the air pressure in the pipe is _______ the pressure exerted by the liquid at the bottom of the tank.
A. Less then
B. Equal to
C. Twice
D. Three times
B. Equal to
- As the temperature rises in a closed vessel, the pressure:
A. Increases
B. Decreases
C. Stays the same
D. Increases then decreases
A. Increases
- When a dip pipe ( bubbler ) system is used for tank level measurement, the dip pipe is connected to:
A. An unregulated gas
B. The low side of the DP
C. The high side of the DP cell
D. The DP cell output signal line
C. The high side of the DP cell
- The temperature of the product in a storage tank increases. What device will still give an accurate signal indicating the true mass in the tank without additional calculations?
A. Load cell
B. DP cell
C. Thermal element
D. Float
A. Load cell
- In which of the following does increasing signal pressure cause the actuator stem to retract and close a valve?
A. Direct action, air to close
B. Direct action, air to open
C. Reverse action, air to close
D. Reverse action, air to open
C. Reverse action, air to close
- A field mounted pressure device that changes a process variable measurement into a signal that can be used by a receiving instrument located in the control room:
A. Bellows
B. Signal conditioner
C. D/P transmitter
D. Signal converter
C. D/P transmitter
- The pressure taps in a standard set of orifice flanges are located _________ upstream from the leading edge of the orifice, and ___________ downstream from the trailing edge of the orifice plate.
A. 8 inches, 5 inches
B. 5 inches, 8 inches
C. 30 inches, 10 inches
D. 1 inch, 1 inch
D. 1 inch, 1 inch
- A bench test of a spring and diaphragm actuator with a positioner shows that full stem travel is not obtained even when full supply pressure is available to the positioner. Which of the following conditions is the most likely cause of the problem?
A. The actuator diaphragm area is too large
B. The stem is too thick
C. A stem travel stop is out of adjustment
D. The spring is too weak
C. A stem travel stop is out of adjustment
- The oil within the variable capacitor of the capacitance type differential pressure transmitter is separated from the process by:
A. And O-ring
B. Capacitor plates
C. Isolating diaphragms
D. Bellows
C. Isolating diaphragms
- The leakage of a metal seated valve may be reduced by a process called:
A. Lapping
B. Calibrating
C. Linearizing
D. Characterizing
A. Lapping
- The results of an orifice plate installed with the bevel on the wrong side is:
A. Damage to the plate
B. Erratic meter readings
C. High meter readings
D. Low meter readings
D. Low meter readings
- When selecting calibration equipment, a CST must verify that the:
A. Calibration equipment is more accurate than the device to be calibrated
B. Device to be calibrated is more accurate than the test equipment
C. Controller positioning the control valve is accurate
D. Process is diverted from the device to be calibrated
A. Calibration equipment is more accurate than the device to be calibrated
- The output signal from a digital control system can NOT be in response to _________ input.
A. One
B. More than one
B. Less than one
D. An analog
C. Less than one
- A pneumatic controller’s output is a function of the spacing between a baffle and a nozzle. A change in the baffle-nozzle relationship produces an increase or decrease in back pressure that is sensed by the relay. This flapper nozzle relationship is determined by the:
A. Relay
B. Output signal
C. Input signal
D. Supply air signal
C. Input signal
- Dewpoint in an instrument air supply system is usually measured:
A. After the air leaves the separator
B. After the air leaves the dryer
C. Before the air enters the dryer
D. Before the air enters the receiver
B. After the air leaves the dryer
- An analog multimeter may be used to measure:
A. Frequency
B. Cycles
C. Voltage
D. Pressure
C. Voltage
- The time it takes for an instrument to start a change in output in response to a change in input is called:
A. Reaction time
B. Dead time
C. Lead time
D. Deviation time
B. Dead time
- As the temperature of the liquid increases, its density:
A. Increases
B. Doubles
C. Remains the same
D. Decreases
D. Decreases
