Deck 4: Analog Processes Control Devices, Sensors and Safety

Question 1

Designers use pneumatic actuators for heavy loads that require a slow and precise movement.

Answer 1

False

Question 2

A solenoid valve is an electromechanical device that can control the flow of an inert gas.

Answer 2

True

Question 3

The exhaust port of a solenoid valve returns fluid accumulated in the cylinder back to the fluid supply.

Answer 3

True

Question 4

The letter T in a solenoid valve symbol indicates that the port is open.

Question 5

Op amp integrators provide a ramp function as the input to the proportional control valve.

Question 6

Pneumatic -assisted valves are used as pilot valves to control the flow to a solenoid valve.

Question 7

A current -to -pressure converter allows the pneumatic -assisted valve to operate over the range of full open to full closed.

Question 8

The current -to -pressure converter is also known as a C/P converter.

Question 9

Thermal capacitance is inversely proportional to heat flow.

Question 10

A photocell changes voltage when exposed to light.

Question 11

Calibration is the process where a set of known values are applied to a sensor -transmitter combination, and the corresponding output values are measured.

Question 12

The calibration curve is not applicable to non -linear systems.

Question 13

Celsius is generally the temperature scale used in industry.

Question 14

The resistance coefficient of pure metal is expressed in ohms per degree Celsius.

Question 15

The RTD's change in resistance must be converted to a change in voltage or current so it can be usable.

Question 16

A three -terminal RTD mitigates the errors caused by lead wire resistance and noise.

Question 17

The temperature coefficient of a thermistor can be either positive or negative by connecting its control input to ground.

Question 18

When the design needs a thermistor with a linear output as a function of temperature, the negative coefficient thermistor is selected.

Question 19

The Seebeck effect is that a small amount of current will flow in a pair of wires that are connected at both ends when one end is heated.

Question 20

Thermocouples are made from two dissimilar metals.

Question 21

The Bourdon tube uses a vibrating U -shaped tube to measure pressure.

Question 22

A diaphragm is a flexible membrane that is made of rubber for high pressure measurements and metal for low pressure measurements.

Question 23

The Seebeck effect occurs when pressure is applied to a crystal so that the crystal deforms and produces a small voltage.

Question 24

Strain can either be positive (compression) or negative (tensile).

Question 25

Gage factor is a ratio of a change in resistance to a change in length.

Question 26

The dummy gage is used in a bridge circuit to compensate for temperature changes that impact the resistance of the active gage.

Question 27

Flow rate through a pipe is inversely proportional to the cross -sectional area of the pipe.

Question 28

An orifice plate is a non -intrusive flow sensor.

Question 29

A venturi is a non -intrusive flow sensor.

Question 30

The thermal mass flow sensor operates independent of density, pressure and viscosity.

Question 31

Besides a temperature sensor, the thermistor is used as a level sensor.

Question 32

There are two classifications of level sensors -- point contact and continuous.

Question 33

Radar level sensor operates well when the surface of liquid is foamy.

Question 34

The magnitude of the output of the LVDT sensor increases regardless of the direction of movement from the null position.

Question 35

The disadvantage of the bubbler level sensor is that the sensor is submerged in the liquid.

Question 36

The potentiometers used as position sensors have billions of operations, yielding a long life expectancy.

Question 37

Specific gravity is the ratio of the density of the item to the density of air.

Question 38

Density is typically expressed as grams per square centimeter or pounds per square foot.

Question 39

A vibrating element can be used as a density sensor.

Question 40

Fluids with higher viscosity flow more easily than those with a lower viscosity.

Question 41

Which of the following is not a control device used on the output side of a process?

A) Heating element
B) Actuator
C) Pyrometer
D) Solenoid
E) Valve

Question 42

Which of the following control valves cannot provide for variable positions over a range of 0% to 100%?

A) Motor driven value
B) Pneumatic -assisted valve
C) Solenoid valve
D) Proportional valve

Question 43

__________as a function of temperature is not a classification of a temperature sensor.

A) Inductance
B) Voltage
C) Resistance
D) Radiation

Question 44

Which of the following is not a classification of a pressure sensor?

A) Direct
B) Integrator
C) Differential
D) Piezoelectric
E) Deflection

Question 45

Which is not a classification of a flow sensor?

A) Distance
B) Displacement
C) Mass
D) Deflection
E) Differential

Question 46

Match the valve type to the application

-Medical respirators

A) Proportional control valve
B) Pneumatic-assisted control value
C) Motor driven control valu

Question 47

Match the valve type to the application

-Paint delivery system

A) Proportional control valve
B) Pneumatic-assisted control value
C) Motor driven control valu

Question 48

Match the valve type to the application

-Control the liquid through large -diameter pipes

A) Proportional control valve
B) Pneumatic-assisted control value
C) Motor driven control valu

Question 49

Match the valve type to the application

-Control the flow of liquid in explosive atmosphere conditions

A) Proportional control valve
B) Pneumatic-assisted control value
C) Motor driven control valu

Question 50

Match the valve type to the application

-Control a damper in an air conditioning system

A) Proportional control valve
B) Pneumatic-assisted control value
C) Motor driven control valu

Question 51

Match the device to its function.

-Transmitter

A) A device that resizes a signal to meet the requirements of another device
B) A device that converts one level of signal to another level
C) A device that converts small signals to larger signals
D) A device that receives one type of energy and concerts it to another typ

Question 52

Match the device to its function.

-Transducer

A) A device that resizes a signal to meet the requirements of another device
B) A device that converts one level of signal to another level
C) A device that converts small signals to larger signals
D) A device that receives one type of energy and concerts it to another typ

Question 53

Match the device to its function.

-Signal Conditioner

A) A device that resizes a signal to meet the requirements of another device
B) A device that converts one level of signal to another level
C) A device that converts small signals to larger signals
D) A device that receives one type of energy and concerts it to another typ

Question 54

Match the advantage to its temperature sensor.

-Very stable

A) Thermistor
B) Thermocouple
C) IC temperature sensor
D) RTD

Question 55

Match the advantage to its temperature sensor.

-Very accurate

A) Thermistor
B) Thermocouple
C) IC temperature sensor
D) RTD

Question 56

Match the advantage to its temperature sensor.

-Fast reaction to temperature change

A) Thermistor
B) Thermocouple
C) IC temperature sensor
D) RTD

Question 57

Match the advantage to its temperature sensor.

-Operates over a large temperature range

A) Thermistor
B) Thermocouple
C) IC temperature sensor
D) RTD

Question 58

Match the advantage to its temperature sensor.

-Most linear

A) Thermistor
B) Thermocouple
C) IC temperature sensor
D) RTD

Question 59

Match the advantage to its temperature sensor.

-Most inexpensive

A) Thermistor
B) Thermocouple
C) IC temperature sensor
D) RTD

Question 60

Match the flow sensor with its classification.

-Orifice plate

A) Differential flow sensor
B) Velocity flow senso

Question 61

Match the flow sensor with its classification.

-Venturi

A) Differential flow sensor
B) Velocity flow senso

Question 62

Match the flow sensor with its classification.

-Pitot tubes

A) Differential flow sensor
B) Velocity flow senso

Question 63

Match the flow sensor with its classification.

-Paddlewheel

A) Differential flow sensor
B) Velocity flow senso

Question 64

Match the flow sensor with its classification.

-Turbine

A) Differential flow sensor
B) Velocity flow senso

Question 65

Match the flow sensor with its classification.

-Vortex

A) Differential flow sensor
B) Velocity flow senso

Question 66

Match the flow sensor with its classification.

-Electromagnetic

A) Differential flow sensor
B) Velocity flow senso

Question 67

Match the flow sensor with its classification.

-Ultrasonic

A) Differential flow sensor
B) Velocity flow senso

Question 68

ISO is the acronym for international organization for standardization.

Question 69

OSHA sets safety standards to save lives, prevent injuries in the work place and protect the health of the American worker.

Question 70

For energized electrical equipment fires, foam or loaded steam is the recommended extinguishing media.

Question 71

The MSDS is a document that lists safety situations for employees who work in a hazardous job.

Question 72

The proximity laser sensor can cover a 180 degree field of view but cannot pattern an irregular shaped area.

Question 73

In a light curtain, an emitter sends an array of synchronous serial infrared light beams to a receiver.

Question 74

The photo transistors in the light curtain receiver detect only specific pulses at a designated frequency of the sending device.

Question 75

The blanking control halts the operation of the light curtain, allowing automatic feeding of materials through the curtain.

Question 76

In the safe distance formula (Ds = K x (Ts + Tc + Tr + Tbm) + Dpf), the letter K is the hand speed constant.

Question 77

The electrical representation of a presence sensing mat is a normally open switch.

Question 78

The control circuitry for presence sensing mats offer remote access to status functions.

Question 79

The switch safety contacts in an interlock device exhibits positive -mode operation, which overcomes the problem of sticking contacts.

Question 80

The block in the figure below with the letter T is the power interlocking block.
?