Book 9

Question 1

The forms commonly used for power-plant equipment control include analog, digital, mechanical, pneumatic and:
Select one:

a.
Electrical

b.
Manual

c.
Thermal

d.
Magnetic

Answer 1

Electrical

Question 2

Thermometers, pressure gauges, and level indicators in the field are known as what?

a.
Errors

b.
Recorders

c.
Indicators

d.
Transmitters

Answer 2

Indicators

Question 3

A basic electric control circuit has 2 major pieces

Select one:

a.
sensor switch and final control element

b.
sensor and thermostat

c.
controller and sensor

d.
solenoid valve and final control element

Answer 3

sensor switch and final control element

Question 4

A device which will cause a visible light signal to become an instrument analog signal is the:
Select one:

a.
Photoelectric transducer

b.
Controller

c.
PE switch

d.
Current-to-pneumatic transducer

Answer 4

Photoelectric transducer

Question 5

Only certified “Safety PLCs” can be used for

Select one:

a.
Air dryer sequencing

b.
Conveyor sequencing

c.
Lime mud mixing systems

d.
Burner management systems

Answer 5

Burner management systems

Question 6

Which is NOT an example of wireless transmission protocol?

a.
Wireless HART

b.
Wi-Fi

c.
Fibre optic

d.
Bluetooth

Answer 6

Fibre optic

Question 7

A two-position controller compares conditions to a set point and:
Select one:

a.
Starts or stops a process

b.
Modulates the final control element

c.
Automatically readjusts the set point

d.
Maintains the final control element position at 50%

Answer 7

Starts or stops a process

Question 8

A valve which gives good throttling action, takes less actuator force, but does not seal well is a:
Select one:

a.
Double seated valve

b.
Reverse acting valve

c.
Single seated valve

d.
Direct acting valve

Answer 8

Double seated valve

Question 9

Fail-closed solenoid operated valves open when
Select one:

a.
a coil is electrically energized

b.
pressure below the valve disc overcomes the spring pressure above the disc

c.
an electric motor opens the valve

d.
it is de-energized

Answer 9

a coil is electrically energized

Question 10

A control loop controller:
Select one:

a.
Sends a signal to a primary element

b.
Measures the manipulated variable value, eliminating the need of a primary element

c.
Eliminates all setpoint deviation

d.
Constantly compares a process variable to the set point

Answer 10

Constantly compares a process variable to the set point

Question 11

A sensing element sends its signal to
Select one:

a.
a transmitter

b.
an air line

c.
a conveyer

d.
a recorder

Answer 11

a transmitter

Question 12

Cascade control utilizes:
Select one:

a.
One controller, two transmitters and two valves

b.
Two controllers, one transmitter and two valves.

c.
Two controllers, two transmitters and two valves.

d.
Two controllers, two transmitters and one valve.

Answer 12

Two controllers, two transmitters and one valve.

Question 13

Depending on the process application, control valves are selected to do all of the following except one:

a.
Fail closed

b.
Fail in the last position (fail first)

c.
Fail open

d.
Fail in the last position (fail last)

Answer 13

Fail in the last position (fail first)

Question 14

A PLC needs to be able to check itself for safe operation. This occurs during the:

Select one:

a.
maintenance scan

b.
program scan

c.
input scan

d.
housekeeping scan

Answer 14

housekeeping scan

Question 15

Which chart recorder came first?

a.
Circular strip

b.
Strip

c.
Circular

d.
Strip chart circular

Answer 15

Circular

Question 16

An open loop control system requires:
Select one:

a.
A transducer and a recorder

b.
More accurate sensing devices

c.
A very small amount of dead time or lag

d.
Constant operator attention

Answer 16

Constant operator attention

Question 17

Where are programs stored if they are always required and must not be modified?

a.
Random access memory (RAM)

b.
Erasable program read-only memory (EPROM)

c.
Hard disk drive (HDD)

d.
Read-only memory (ROM)

Answer 17

Read-only memory (ROM)

Question 18

Transmitters with built-in microprocessors are known as:
Select one:

a.
Digital transmitters

b.
Smart transmitters

c.
Analog transmitters

d.
Modems

Answer 18

Smart transmitters

Question 19

Level, pressure, flow, and temperature are examples of:
Select one:

a.
Transmitters

b.
Measured variables

c.
Sensing elements

d.
Manipulated variables

Answer 19

Measured variables

Question 20

Electro-hydraulic valves open slowly when energized. However, when electric power is interrupted, a powerful _____________ quickly slams the valve shut, thereby stopping the fuel flow to the burner.

a.
Motor

b.
Spring

c.
Bellows

d.
Diaphragm

Answer 20

Spring

Question 21

A thermocouple measures:
Select one:

a.
Pressure

b.
Temperature

c.
Velocity

d.
Light

Answer 21

Temperature

Question 22

What is a computer program?

a.
A collection of wires and silicon chips

b.
A series of signals from transmitters

c.
A series of instructions to do a task

d.
A series of tasks for the operator

Answer 22

A series of instructions to do a task

Question 23

A controller is a device that primarily:
Select one:

a.
Sends or transmits a positive rather than negative signal

b.
Tries to maintain a set point

c.
Records a system’s performance

d.
Is a logic device capable of making decisions

Answer 23

Tries to maintain a set point

Question 24

The capability of modular PLCs can be expanded by adding___________.

Select one:

a.
memory

b.
hard drives

c.
input and output cards

d.
transmitters and receivers

Answer 24

input and output cards

Question 25

A circular chart recorder: Select one: a. Provides a different function than a strip chart. b. Is newer design than a strip chart. c. Incorporates a bourdon tube. d. Does not provide a permanent record.

Answer 25

Incorporates a bourdon tube.

Question 26

One of the most important and commonly measured process variables in a system is: Select one: a. Viscosity b. Pressure c. Density d. Composition

Answer 26

Pressure

Question 27

The inclined “U” tube manometer: Select one: a. Will measure pressure in kPa b. Can only be used with mercury c. Is more accurate than the “U” tube manometer d. Is more difficult to read than the U-tube manometer Feedback

Answer 27

Is more accurate than the “U” tube manometer

Question 28

When a basic differential pressure transmitter is used for flow measurement: Select one: a. The low-pressure side is upstream of the orifice plate. b. The transmitter sends a signal directly to the final control element. c. Output signal varies with the flow. d. Air supply pressure varies with the flow.

Answer 28

Output signal varies with the flow.

Question 29

Integral and Derivative functions Select one: a. may be combined with multi-position controllers b. are also called feed-forward and cascade functions c. help to maintain a process variable on set-point. d. are used in on-off control.

Answer 29

help to maintain a process variable on set-point.

Question 30

When a float is used for measuring level, and installation within a vessel is impractical, the float is installed in a Select one: a. Float manometer b. Float cage c. Differential head meter d. Diaphragm level indicator

Answer 30

Float cage

Question 31

What types of service are nutating discs not suitable for? a. Low pressure or high temperature b. High pressure or low temperature c. High pressure or high temperature d. Low pressure or low temperature Feedback

Answer 31

High pressure or high temperature

Question 32

Approved Burner Management Systems used on smaller packaged boilers: Select one: a. are fully-configurable by field operators, using an HMI b. have a limited selection of field-configurable parameters, such as purge, trial for ignition and flame failure response time c. have fully configurable sequences and operating parameters d. can only be set up by burner technicians using laptop computers and ladder logic

Answer 32

have a limited selection of field-configurable parameters, such as purge, trial for ignition and flame failure response time

Question 33

Which devices are used by an electronic control system? a. Sensors and transmitters b. Rectifiers and inverters c. Monitors and modems d. Resistors and transistors

Answer 33

Sensors and transmitters

Question 34

An analog control loop output must be put through a _____ before the computer can react to the signal. Select one: a. Digital converter b. Signal inverter c. ROM detector d. Multiplexer

Answer 34

Digital converter

Question 35

Computer software used for managing maintenance cannot: Select one: a. prepare scheduled maintenance work orders b. manually verify equipment and parts inventory c. track equipment operating times d. generate maintenance cost reports

Answer 35

manually verify equipment and parts inventory

Question 36

In a pneumatic control system, the nozzle receives a regulated air supply pressure of approximately: Select one: a. 140 Pa b. 20 kPa c. 140 kPa d. 200 kPa

Answer 36

140 kPa

Question 37

In an automatic control system the controller output signal goes to the: Select one: a. Transmitter b. Sensing element c. Final control element d. Process variable

Answer 37

Final control element

Question 38

In an automatic control system, the controller output signal changes the position of the: Select one: a. Recorder b. Transmitter c. Sensing element d. Final control element

Answer 38

Final control element

Question 39

Pressure controllers can be divided into two classes: Select one: a. High and low temperature b. High and low pressure c. High and low flow d. High and low voltage

Answer 39

High and low pressure

Question 40

Which type of controller can respond before the change takes place? a. Proportional b. Integral c. Feedback d. Feedforward

Answer 40

Feedforward

Question 41

The electrical output from a thermocouple is measured by a: Select one: a. Milliamp meter b. Watt meter c. Milliwatt meter d. Millivolt meter

Answer 41

Millivolt meter

Question 42

When are modulating motors used? a. To position valves and dampers b. As electromechanical actuators c. For two-position control of steam or hot water to radiators d. To operate two-position valves

Answer 42

To position valves and dampers

Question 43

What is one advantage of a modular PLC? a. Input and output cards can be added or removed b. Input or output cards cannot be swapped for other kinds of cards c. Self-contained similar to monolithic PLC d. Defective cards cannot be replaced

Answer 43

Input and output cards can be added or removed

Question 44

A valve actuator: Select one: a. Cannot be reverse acting b. Will always have one side of the diaphragm open to atmosphere c. Is a two-position device d. Position is a function of controller output

Answer 44

Position is a function of controller output

Question 45

A computer displays information to the operator via Select one: a. a monitor b. an icon c. a CAD d. a CPU

Answer 45

a monitor

Question 46

Why were PLCs first developed? Select one: a. To remove the need for feedback loops b. To eliminate the need for control programming language c. To allow processes to be easily and quickly re-configured d. To allow the use of analog input and output signals

Answer 46

To allow processes to be easily and quickly re-configured

Question 47

A thermocouple consists of: Select one: a. Two dissimilar wires connected together to form a measuring and a reference junction b. Two dissimilar wires connected to a battery c. A thermally-conductive fluid, held within a fine tube d. A thermistor, coupled to a wheatstone bridge

Answer 47

Two dissimilar wires connected together to form a measuring and a reference junction

Question 48

Digital output signals are processed by _____ before an analog controls can react to them. Select one: a. Digital receivers b. Logic controllers c. the CPU d. Analog converters

Answer 48

Analog converters

Question 49

Orifice plates, venturi tubes and nozzles belong to the group called: Select one: a. Flow meters b. Pressure meters c. Head meters d. Analog meters

Answer 49

Head meters

Question 50

A proportional controller: Select one: a. Is also called a multi-position controller b. Provides a proportional output based on the error between process variable and set-point c. Provides on-off control d. Allows the process variable to always be maintained at the set-point

Answer 50

Provides a proportional output based on the error between process variable and set-point

Question 51

What are the essential components of a modular PLC? a. Panel lights and warning lights b. Three discrete inputs and two analog output cards c. Transmitters and CPU d. Power supply and CPU

Answer 51

Power supply and CPU

Question 52

The variable area meter consists of: Select one: a. A fluid being measured, flowing through the tube from the top to the bottom b. A float across which the differential pressure varies c. A tapered tube in which the fluid being measured flows through the tube from the bottom to the top d. An opening that can be varied as required

Answer 52

A tapered tube in which the fluid being measured flows through the tube from the bottom to the top

Question 53

Automatic systems that can make decisions are termed: Select one: a. Annunciation systems b. Indicating systems c. Logic systems d. Open loop systems

Answer 53

Logic systems

Question 54

A Bourdon tube may be manufactured in the shape of a helix so that _______________________ than a standard bourdon tube: Select one: a. Its final output has less travel b. They can fit in narrower enclosures c. Higher pressures can be sensed d. It has enough power and rotation to move the pens of a recorder without the use of gears

Answer 54

It has enough power and rotation to move the pens of a recorder without the use of gears

Question 55

In a basic electrical control system the device that senses a drop in air temperature is called the: Select one: a. Final controlled device b. Pneumatic temperature sensor c. Humidistat d. Thermostat

Answer 55

Thermostat

Question 56

A control device which will change one form of energy into another form of energy is the: Select one: a. Logic device b. Primary element c. Transducer d. Transmitter

Answer 56

Transducer

Question 57

A PLC with an HMI can signal an alarm by: (choose all that are correct) Select one or more: a. Sounding a siren or horn b. Flashing an equipment icon on the HMI screen c. Operating a beacon d. Turning the HMI screen a different colour

Answer 57

Sounding a siren or horn, Operating a beacon, Flashing an equipment icon on the HMI screen, Turning the HMI screen a different colour

Question 58

The apparatus which converts current signals to pneumatic and pneumatic to current signals is called a: Select one: a. Converter b. Inverter c. Transducer d. Transformer Feedback

Answer 58

Transducer

Question 59

Which of the following is an advantage of electrical control systems? Select one: a. Electricity is readily available b. The necessary computer programming is easy to learn c. Controller/actuators require a dedicated air supply lowering the power requirements d. Signals from sensing elements produce one discrete digital output

Answer 59

Electricity is readily available, Controller/actuators require a dedicated air supply lowering the power requirements

Question 60

What is the approximate arc of a bourdon tube pressure gauge? a. 270° b. 280° c. 260° d. 290°

Answer 60

270

Question 61

Which two types of ultrasonic flow meters are commonly in use? a. Transit-time and Doppler b. Weir and Coriolis c. Transit-time and Doppler effect d. Magnetic and variable area

Answer 61

Transit-time and Doppler

Question 62

Name the control loop in which no check is made to determine whether the corrective action has accomplished the desired objective. a. Feedback b. Closed c. Open d. Partial

Answer 62

Open

Question 63

A flowing liquid has kinetic energy as a function of its velocity. When its velocity increases Select one: a. Potential energy in the form of pressure will also increase b. The cross-sectional area of the piping must increase c. The mass quantity flowing per second will decrease d. Potential energy in the form of pressure will decrease

Answer 63

Potential energy in the form of pressure will decrease

Question 64

A helix strip bimetallic thermometer is wound spirally to: Select one: a. Dampen the motion of the pointer b. Ease its installation c. Increase the range of temperature it can measure d. Amplify the motion of the pointer

Answer 64

Amplify the motion of the pointer

Question 65

Pneumatic signals operate between: Select one: a. 20 and 200 kPa b. 0 and 100 kPa c. 50 and 500 kPa d. 20 and 100 kPa

Answer 65

20 and 100 kPa

Question 66

A sensing element responds to the value of the Select one: a. Controller b. Recorder c. Control valve d. Measured variable

Answer 66

Measured variable

Question 67

The Bourdon tube is often shaped in the form of a “C”, having an arc span of about: Select one: a. 180 degrees b. 200 degrees c. 90 degrees d. 270 degrees Feedback

Answer 67

270 degrees

Question 68

A _______ is NOT a discrete input. Select one: a. limit switch b. temperature sensor c. push button d. proximity switch

Answer 68

temperature sensor

Question 69

If the combustion air pressure is too low to deliver the correct amount of combustion air, what will the low-pressure controller do? a. Close an electric circuit and close the fuel valves b. Open an electric circuit and open the fuel valves c. Open an electric circuit and close the fuel valves d. Close an electric circuit and open the fuel valves

Answer 69

Open an electric circuit and close the fuel valves

Question 70

PLCs are commonly used for: Select one: a. packaged boiler burner management systems b. operating equipment in the correct sequence c. simultaneous manual control of several control devices d. running maintenance software.

Answer 70

operating equipment in the correct sequence

Question 71

What are the basic logic conditions? a. TRUE, FALSE, NEITHER b. UP, DOWN, MIDDLE c. YES, AND, NO d. Not, And, OR

Answer 71

Not, And, OR

Question 72

A variable which is adjusted in order to maintain or achieve some desired value of another variable is termed the: Select one: a. Process variable b. Final variable c. Manipulated variable d. Controlled variable

Answer 72

Manipulated variable

Question 73

The type of circuit used to store (write) and retrieve (read) information from a computer is known as its: Select one: a. Bytes b. Motherboard c. RAM d. ROM

Answer 73

RAM

Question 74

An unpredicted change in a plant process is called a/an: Select one: a. Disruption b. Disturbance c. Error d. Malfunction

Answer 74

Disturbance

Question 75

An orifice plate with a round opening that is centred in the middle of the plate is called a: Select one: a. Concentric orifice b. Eccentric orifice c. Concentric flange d. Centralized flow

Answer 75

Concentric orifice

Question 76

When a process variable has no method of sending information to the final control element (a valve for example) the system is known as: Select one: a. An open loop system b. A cascade system c. A feedback system d. A feedforward system

Answer 76

An open loop system

Question 77

Which of the following is NOT a functionality provided by a human machine interface to the operator? a. Start and stop process b. Acknowledge and reset alarms c. Observe normal and adverse operating conditions d. Reconfigure input and output devices Feedback

Answer 77

Reconfigure input and output devices

Question 78

What are two methods of signal transmission? a. Digital and fibre optic b. Digital and current c. Analog and transducer d. Analog and digital

Answer 78

Analog and digital

Question 79

A proportional-only controller: Select one: a. Are mostly used for on/off control. b. Compare actual conditions to controller outputs. c. Must provide reset action. d. Cannot always maintain the process variable exactly at the set-point.

Answer 79

Cannot always maintain the process variable exactly at the set-point.

Question 80

Putting a controller on manual control means: Select one: a. The operator controls the final control element. b. The controller output responds to a process variable. c. There is no control of the final control element. d. The operator manually adjusts the process by changing the process variable signal

Answer 80

The operator controls the final control element.

Question 81

Which of the following is an advantage of electrical control systems? a. Controller/actuators require a dedicated air supply, lowering the power requirements b. Signals from sensing elements produce one discrete digital output c. Single controller/actuator combinations are possible without the need of a source of compressed air d. The necessary computer programming is easy to learn

Answer 81

Single controller/actuator combinations are possible without the need of a source of compressed air

Question 82

A basic, filled system thermometer consists of a temperature-sensitive bulb, a capillary tube, and a pressure-sensing device. Which pressure-sensing device would suit this purpose? a. Diaphragm b. Rheostat c. Thermistor d. Thermometer

Answer 82

Diaphragm

Question 83

When controller output is proportional to the amount of deviation, the controller is: Select one: a. Integral b. Two-position c. Proportion plus reset plus rate d. Proportional

Answer 83

Proportional

Question 84

Liquids must be vapourized Select one: a. In order to measure density b. If purity is to be measured c. When a chromatograph is being used d. When conductivity is measured

Answer 84

When a chromatograph is being used

Question 85

Control valves Select one: a. Must fail closed b. Provide variable resistance in a piping system c. Provide tight flow shut-off d. Must modulate from fully open to fully shut

Answer 85

Provide variable resistance in a piping system

Question 86

A DC motor used to provide precise repeatable positioning of valves or dampers is the Select one: a. stepper motor b. solenoid c. modulating motor d. Wheatstone bridge

Answer 86

stepper motor

Question 87

The bimetal sensing element consists of a strip made up of two thin layers of metal with: Select one: a. Similar rates of thermal expansion b. Different rates of thermal expansion c. Different specific heats d. Different resistances Feedback

Answer 87

Different rates of thermal expansion

Question 88

The main component of any computer is the: Select one: a. Keyboard b. Screen c. Memory d. Central processing unit

Answer 88

The correct answer is: Central processing unit

Question 89

The filled system thermometer of a remote bulb thermostat maybe filled with a vaporizing liquid that reacts in what way? a. Varies in level with temperature b. Varies in pressure with temperature c. Changes color with temperature d. Changes volume with temperature

Answer 89

Varies in pressure with temperature

Question 90

A “U” tube manometer may be filled with: Select one: a. A granular substance b. Nitrogen c. Ethyl alcohol d. Light oils

Answer 90

Light oils

Question 91

A control valve that has one plug that moves upward to close the port is called: Select one: a. Reverse acting b. Double seated direct acting. c. Reverse acting diaphragm actuated. d. Direct acting

Answer 91

Reverse acting

Question 92

Which part of a transmitter contains the valve capsule, restrictor, spring, and exhaust valve? a. Flapper-and-nozzle b. Pneumatic relay c. Pressure reducer d. Feedback bellows

Answer 92

Pneumatic relay

Question 93

A valve body that seals on the down stroke is: Select one: a. Reverse acting b. Single sealed c. Direct acting d. Double sealed

Answer 93

Direct acting

Question 94

An electrical actuator used to position dampers and control valves is called: Select one: a. A controller b. A relay c. A transformer d. A modulating motor

Answer 94

A modulating motor

Question 95

Which of the following is NOT a component of a modular PLC? a. Digital input/output card b. Central processing unit c. Discrete input card d. Analog input card

Answer 95

Digital input/output card

Question 96

On-off thermostats are equipped with: Select one: a. An open contact switch b. Humidity compensation c. Two or more switches, operated in sequence d. A potentiometer

Answer 96

An open contact switch

Question 97

What is an example of a final control element? a. A thermostat that controls air temperatures in ducts b. A damper motor that operates air louvres c. A rheostat that varies current in a circuit d. A relay that starts/stops a pump

Answer 97

A damper motor that operates air louvres

Question 98

A PLC needs ___________ to accept operator input: Select one: a. an HMI b. an analogue input card c. specialized software d. an internet or network connection

Answer 98

an HMI

Question 99

A recorder utilizing a spiral Bourdon tube will have a pen movement: Select one: a. On a logarithmic scale b. Proportional to the change in tube pressure c. Range of 0 to 24 hours d. Range of 0 to 7 days

Answer 99

Proportional to the change in tube pressure

Question 100

Data cannot be permanently stored on a Select one: a. CD-ROM b. Hard disk c. CPU d. Monitor

Answer 100

Monitor