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Worksheets0-100
Total questions: 103
Worksheet time: 52mins
What is the purpose of an indicator in an instrument system?
To provide a human-readable indication of an instrument signal
To transmit a standard instrument signal
To withstand radiation
To perform conversion calculations
What is a common feature of process transmitters?
They are always equipped with readouts
They just transmit a standard instrument signal to another device
They are always located near the indicators
They can only connect to one indicator
What technology does the field-mounted indicator use for its numerical display to use less electrical power?
Bargraphs
LCD technology
Red-glowing LEDs
Standard instrument signals
What is the purpose of a recorder in an instrument system?
To draw a graph of process variable(s) over time
To withstand radiation
To transmit a standard instrument signal
To perform conversion calculations
What types of recorders are still in use today?
Both circular and strip chart recorders
Only strip chart recorders
Neither circular nor strip chart recorders
Only circular chart recorders
What does the controller do to maintain the process variable at setpoint? PHOTO
It changes its output as necessary
It keeps the output signal constant
It reduces the process variable
It ignores variations in process load
What could a wildly-fluctuating output signal indicate? PHOTO
The control system is working well
The control system is not working well
The process variable is deviating significantly from the setpoint
The controller is in manual mode
What is the delay between when the output signal is “stepped” to a new value and when the process variable responds to the change called? PHOTO
Transport delay
Dead time
Process load
Mechanical friction
What is the purpose of a process switch in a measurement and control system?
To turn on and off with varying process conditions
To withstand radiation
To transmit a standard instrument signal
To perform conversion calculations
What activates the “PSH” (pressure switch, high) and the “PSL” (pressure switch, low)? PHOTO
The air pressure outside the vessel reaching its high control point and dropping down to its low control point, respectively
The air pressure outside the vessel dropping down to its low control point and reaching its high control point, respectively
The air pressure inside the vessel dropping down to its low control point and reaching its high control point, respectively
The air pressure inside the vessel reaching its high control point and dropping down to its low control point, respectively
. What do the labels “AAL” and “AAH” refer to?
Analog alarm low and analog alarm high, respectively
Analog alarm high and analog alarm low, respectively
Analytical alarm high and analytical alarm low, respectively
Analytical alarm low and analytical alarm high, respectively
How do the alarm switches (LSL and LSH) sense water level? PHOTO
They directly sense water level by monitoring the water in the steam drum
They sense water level by monitoring the air pressure in the steam drum
They sense water level by monitoring the temperature in the steam drum
They indirectly sense water level by monitoring the pneumatic signal pressure output by the level transmitter (LT)
Why is neatness important in electrical signal wiring? PHOTO
It makes the electrons move faster
It makes the system look good
It makes the system easier to navigate and troubleshoot
A. It makes the system cheaper
What is the purpose of crimp-style ferrules in terminal block connections? PHOTO
They increase the electrical resistance of the connection
They make the wires easier to cut
They provide a more rugged tip for the terminal block screw
They make the wires look neat
What is the advantage of using multi-level terminal blocks? PHOTO
They allow the placement of actual circuit components near connection points
They are easier to manufacture
They are smaller and lighter than single level terminal blocks
They provide the option of internal jumpers to connect two or more levels together
Why is the use of solid wire necessary with certain terminal blocks?
Because solid wire is more flexible
Because solid wire is cheaper
Because solid wire is more durable
Because stranded wire would become frayed by the combination of forces
Why are compression-style terminals unsuitable for solid wire?
They are too expensive to use with solid wire
They lose their tension rapidly on solid wire
They are not available in the right sizes for solid wire
They are too difficult to install on solid wire
What is the advantage of ring terminals over fork terminals? PHOTO
They are more secure and cannot fall off the connection point
They are easier to install and remove
They are cheaper
A. They are more suitable for use with solid wire
What is a DIN rail?
A narrow channel of metal for terminal blocks
A type of electrical component
A type of electrical wire
A type of screw used in electrical installations
What is a feature of many DIN rail type terminal blocks?
They cannot be attached to any type of DIN rail
They can only be attached to “top hat” DIN rail
They can only be attached to “G” shaped DIN rail
They can be attached to either “top hat” or “G” shaped DIN rail
What is the purpose of using conduit in cable routing? PHOTO
To provide a decorative element to the wiring system
To increase the electrical conductivity of the cables
To support electrical cables and protect them from harsh conditions
To make the cables easier to cut
What is the advantage of using plastic conduit over metal conduit?
Plastic conduit provides better electrical grounding
Plastic conduit is more durable than metal conduit
Plastic conduit is cheaper than metal conduit
Plastic conduit is superior with regard to chemical corrosion resistance
What is the purpose of using flexible liquid-tight conduit when connecting electrical conduit to end-point devices? PHOTO
It makes the conduit easier to cut
It makes the conduit look more attractive
It provides stress relief to the conduit
It increases the electrical conductivity of the conduit
What is a busway used for in industrial facilities? PHOTO
For providing a pathway for workers to walk through the facility
For electrical power distribution
For instrumentation, control, or signaling purposes
For supporting the weight of the building
What is the purpose of wire duct and wire loom in an electrical enclosure? PHOTO
A. To neatly route power, signal, and instrumentation conductors
To increase the electrical conductivity of the wires
To provide a decorative element to the enclosure
To make the wires easier to cut
What is an optical fiber?
A type of electrical cable
A type of LED
A pipe through which light flows
A type of photodiode
What is the predominant use of optical fiber in modern industry?
As a data communication
As a replacement for LED lights
As a source of light for homes
As a replacement for photodiodes
What is one advantage of optical fiber over electrical cable?
It needs to avoid tight bend radii
It requires expensive testing equipment
It requires specialized tools for installation
It has a much greater bandwidth
What is the primary function of the core in an optical fiber? PHOTO
To protect the fiber from abrasion
To provide coloring for fiber identification
To serve as a waveguide for light
A. To channel electrical energy
What is the primary function of the core in an optical fiber? PHOTO
To protect the fiber from abrasion
To provide coloring for fiber identification
To serve as a waveguide for light
A. To channel electrical energy
Why is the cladding layer necessary in an optical fiber? PHOTO
To absorb specific light wavelengths
To provide additional protection against abrasion
To prevent leakage of optical power
To enhance the tensile strength of the cable
Why is the cladding layer necessary in an optical fiber? PHOTO
To absorb specific light wavelengths
To provide additional protection against abrasion
To prevent leakage of optical power
To enhance the tensile strength of the cable
What is the purpose of the plastic jacket around the cladding in an optical fiber? PHOTO
To prevent leakage of optical power
To absorb specific light wavelengths
To provide protection against abrasion
To increase the diameter of the fiber
What is the primary difference between multi-mode fibers and single-mode fibers? PHOTO
Multi-mode fibers are more suitable for high-speed data transmission.
Single-mode fibers support multiple independent pathways within the core
Multi-mode fibers have a larger core diameter than single-mode fibers.
Single-mode fibers exhibit less modal dispersion.
What is the primary difference between multi-mode fibers and single-mode fibers? PHOTO
Multi-mode fibers are more suitable for high-speed data transmission.
Single-mode fibers support multiple independent pathways within the core
Multi-mode fibers have a larger core diameter than single-mode fibers.
Single-mode fibers exhibit less modal dispersion.
What is the typical range of core diameters for single-mode optical fibers? PHOTO
8 microns
20 microns
4 to 10 microns
50 microns or more
What is the typical range of core diameters for single-mode optical fibers? PHOTO
8 microns
20 microns
4 to 10 microns
50 microns or more
. What is the purpose of maintaining a minimum bend radius for optical fibers? PHOTO
To increase the speed of data transmission
A. To prevent light leakage from the cladding
To improve signal strength
To reduce cable weight
What safety concern arises when working with optical fibers during installation or maintenance?
Exposure to toxic chemicals
all answers right
Danger from glass fiber fragments
Risk of electrical shock
What is the purpose of testing optical fibers?
To measure certain performance characteristics
All answers correct
To ensure all installed cable lengths and connectors are functioning properly
To quantify any degradation of cables or connectors over time
Which type of optical fiber test measures the power level of light at the far end of the fiber from a known source? PHOTO
Sophisticated light analysis
Time domain reflectometry.
Echo signal analysis
Optical power loss testing
What does an Optical Time-Domain Reflectometer (OTDR) do? PHOTO
Analyzes light over brief periods
Measures optical power.
Tests connectors on the spool prior to installation.
Probes characteristics of long optical fibers.
. Which type of diagram is used to represent the “big picture” of a process, focusing on the process itself rather than individual instruments?
Functional diagrams
Process Flow Diagrams (PFDs)
Loop diagrams
Process and Instrument diagrams (P&IDs)
What type of diagram is used to document the strategy of a control system, placing emphasis on the algorithms used to control a process?
Process Flow Diagrams (PFDs)
Process and Instrument diagrams (P&IDs)
Functional diagrams
Loop diagrams
Which type of diagram lies somewhere in the middle between process flow diagrams and loop diagrams, showing the layout of all relevant process vessels, pipes, and machinery, with instruments superimposed on the diagram?
Functional diagrams
Process Flow Diagrams (PFDs)
Process and Instrument diagrams (P&IDs)
Loop diagrams
What is the primary purpose of a Process Flow Diagram (PFD) in a compressor control system? PHOTO
To show the interconnections of individual instruments
To document the strategy of a control system
To show the layout of all process vessels, pipes, and machinery with instruments superimposed on the diagram
To show the general flow of the process itself and only a bare minimum of control instrumentation
In the given compressor control system, what might the level transmitter (LT) on the bottom of the knockout drum control? PHOTO
The pressure inside the compressor
The temperature of the evaporator
The level valve (LV) on the bottom of the same vessel
The flow of the compressor
What does the Process Flow Diagram (PFD) show relating directly to the compressor in the given system? PHOTO
The temperature transmitter (TT) on the top of the evaporator
The level transmitter (LT) on the bottom of the knockout drum
The flow transmitter (FT) on the suction line
The control system of the compressor
What does a proximity switch detect
The weight of an object
The closeness of an object
The temperature of an object
The color of an object
What does a Process and Instrument Diagram (P&ID) provide a “zoomed in” view of in a compressor control system? PHOTO
The compressor as a unit
The whole evaporator process
The control system
The individual instruments
In the given compressor control system, what does a common “loop number” indicate? PHOTO
The instruments are part of different control systems
The instruments are of the same type
The instruments are physically connected
The instruments are part of the same control system
What does the type of “bubble” used for each instrument in a P&ID indicate? PHOTO
The function of the instrument
The loop number of the instrument
The type of the instrument
The location of the instrument
. What does a rectangular box enclosing both temperature recorders in a P&ID indicate? PHOTO
A. The temperature recorders are part of different physical instruments
The temperature recorders are malfunctioning
The temperature recorders are of different types
The temperature recorders are part of the same physical instrument
. What is the most detailed form of diagram for a control system as a whole?
Functional diagram
Process and Instrument Diagram (P&ID)
Process Flow Diagram (PFD)
Loop diagram
What does an “up” arrow (↑) next to an instrument bubble in a loop diagram represent? PHOTO
A reverse-acting instrument: one whose output signal decreases as the input stimulus increases
A direct-acting instrument: one whose output signal increases as the input stimulus increases
An instrument that is not part of the control system
An instrument that is malfunctioning
. What is the primary focus of a functional diagram in a control system? PHOTO
The process piping or instrument interconnections
The flow of information within the control system
The actual equipment layout
A. The final control element
In a functional diagram, what do rectangular blocks represent? PHOTO
The final control element
Automatic functions
Manual functions set by a human operator
The process sensing instrument
In a functional diagram, what do dashed lines represent? PHOTO
The layout of all relevant process vessels, pipes, and machinery
The flow of the process
Analog (continuously variable) signals
Discrete (on/off) signal paths
What is the “normal” status of a switch? PHOTO
The status when the switch is in motion
The status when the switch is at rest and not under physical stimulation
The status when the switch is under physical stimulation
The status when the switch is being pressed
What is the “normal” condition for a flow switch?
High flow rate (fluid flowing)
Medium flow rate (fluid flowing slowly)
No specific flow rate
Low flow rate (fluid stopped)
What is the “normal” condition for a flow switch?
High flow rate (fluid flowing)
Medium flow rate (fluid flowing slowly)
No specific flow rate
Low flow rate (fluid stopped)
What is a pushbutton?
An electrical switch actuated by a person’s eye movement
An electrical switch actuated by a person’s foot motion
An electrical switch actuated by a person’s hand motion
An electrical switch actuated by a person’s voice
What does a limit switch detect?
The electrical current of an object
The temperature of an object
The physical motion of an object by direct contact
The weight of an object
What is a form-C contact set in the context of a limit switch?
It does not incorporate any contacts
It incorporates only a form-B contact (normally-closed)
It incorporates both a form-A contact (NO) and a form-B contact (NC)
It incorporates only a form-A contact (normally-open)
. How do inductive proximity switches sense the presence of metallic objects?
Through the use of a high-frequency light beam
Through the use of a high-frequency sound wave
Through the use of a high-frequency magnetic field
Through the use of a high-frequency electric field
How do ultrasonic proximity switches sense the presence of dense matter?
By the reflection of sound waves
By the reflection of magnetic fields
By the reflection of electric fields
By the reflection of light waves
. By the reflection of light waves
Pistons
Diaphragms or bellows
Gears
Springs
What is a disadvantage of mercury tilt switches?
They are insensitive to oil mist
They are insensitive to corrosion
They are insensitive to dust
They are sensitive to mounting angle
What is often used as the level-sensing element in level switches?
Floats
Pistons
Springs
Gears
Where can simpler float switch designs be directly installed?
In closed process vessels
In open (vented) process vessels
In any type of process vessel
In isolated process vessels
How does a tuning-fork style level switch indicate the presence of mass contacting the fork?
The resonant frequency of the fork disappears
The resonant frequency of the fork increases
The resonant frequency of the fork decreases
The resonant frequency of the fork remains the same
What is often used as the temperature-sensing element in temperature switches?
Floats
Springs
Diaphragms and Bellows
Bimetallic strips
What is often used as the flow-sensing element in flow switches?
Floats
Pistons
Paddles
Bimetallic strip
What happens when a paddle in a flow switch is placed in the midst of a fluid stream?
It generates an electricity which used to actuate a switch mechanism
It generates sound waves which used to actuate a switch mechanism
It breaks the electrical circuit
It generates a mechanical force which used to actuate a switch mechanism
What is the function of an on/off valve?
To increase the flow of fluid
To either allow flow or prevent flow
To decrease the flow of fluid
To measure the flow of fluid
Fluid systems can be broadly grouped into which two categories?
Gas and Solid
Hot and Cold
Pneumatic and Hydraulic
Solid and Liquid
. What type of valve is used in pneumatic and hydraulic systems to direct the pressurized fluid to different locations?
Gate Valve
Spool Valve
Butterfly Valve
Ball Valve
What is the purpose of a filter at the inlet of the pump in all hydraulic systems?
To heat the hydraulic fluid
To decrease the pressure of the fluid
To remove particulate impurities from the fluid
To increase the pressure of the fluid
What is an advantage of fluid power systems over electric power?
Fluid power systems are easier troubleshoot than electric systems
Fluid power motors and cylinders overload at low speeds
Fluid power systems present a high fire hazard
Fluid power systems cannot be used in submerged environments
What is a characteristic of pneumatic systems?
They are not self-purging
They can use liquefied nitrogen as a back-up gas supply
They produce a lot of sparks
They are difficult to equip with a back-up energy reserve
What must pneumatic (instrument air) systems be free of?
Water vapor and particulate contamination
Liquefied nitrogen
Desiccants
Hydraulic oil
How is the moisture content in instrument air often expressed?
Dew point
Moisture index
Wetness
Humidity
What is the purpose of the “wingnut” drain at the bottom of the regulator?
To measure the amount of water in the compressed air
To add water to the compressed air
To purge collected water from the basin
To increase the pressure of the compressed air
What is a solenoid in the context of a solenoid valve?
A coil of wire
A type of magnetic field
type of fluid
A type of valve mechanism
. How are solenoid-actuated valves usually classified?
According to the type of fluid they control
According to the number of ports (“ways”)
According to the type of magnetic field they produce
According to the size of the solenoid coil
. What do the letters “P,” “E,” and “C” commonly represent on a pneumatic 3- way valve?
Pump, Evaporator, and Condenser
Positive, Earth, and Common
Pressure, Exhaust, and Cylinder
Power, Energy, and Current
. In a hydraulic system, what does the letter “T” represent when used as a label for a port?
Tank
Temperature
Transformer
Turbine
. What kind of spool valve appears here:
2 way spool valve
4 way spool valve
5 way spool valve
3 way spool valve
. When two or more bare conductors touch causing the resistance between the two to drop
A. Electrical shock
Short circuit
Ground fault
Overload
When the current exceeds the trip class of the device
Overload
Electrical shock
Short circuit
Ground fault
Inadvertent contact between an energized conductor and ground or equipment frame
Overload
Short circuit
Ground fault
Electrical shock
. What is the primary function of a contactor?
A. To handle high motor starting currents.
To regulate voltage fluctuations.
To protect the motor from overload.
To switch auxiliary circuits in control systems.
Which component is used in conjunction with contactors for motor protection?
Circuit breaker
Industrial control relay
General purpose relay.
Overload relay
What type of circuits do industrial control relays switch?
High-voltage circuits
Auxiliary circuits
Lighting circuits
Low amperage circuits
How is a general purpose relay different from an industrial control relay?
General purpose relays are physically larger.
General purpose relays are for low amperage current.
General purpose relays are more expensive.
General purpose relays handle higher currents.
How does a contactor differ from a relay?
Contactors switch 3 phases, while relays switch single-phase circuits.
Contactors are only used in industrial settings
Contactors are used for low amperage current, while relays handle high currents.
Contactors are controlled by electronic systems, while relays are manually operated.
. What is the purpose of time delay relays?
To switch auxiliary circuits
To control motor speed
To protect the motor from overload
To open or close contacts based on timing
What is the purpose of mechanical interlocking in contactors?
To save power during voltage interruptions.
To prevent short-circuits during manual actuation
To prevent surges in the control circuit.
To allow simultaneous closing of two contactors
What is the purpose of a mechanical latch in a contactor?
To allow the contactor to return to its rest position.
To prevent the contactor from dropping out.
To switch auxiliary circuits
To energize the coil.
What is the primary function of a thermal overload relay?
To detect excessive load in the circuit.
To monitor incoming voltage.
To trip the contactor coil circuit.
To prevent motor overheating
How does an electronic overload relay monitor current?
Using phase failure protection
By measuring temperature.
Via built-in voltage transformers.
Through current transformers
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