Automation Controls Flashcards

1
Q

What type of control system would the O/P and I/P align steady state conditions?

A

Positional

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2
Q

what type of control system would a finite error exist when operating normally?

A

Regulatory

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3
Q

which term describes positive feedback?

A

Regenerative

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4
Q

on the block diagram of an open loop control system, what is the following term to refers as the input

A

Desired Value

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5
Q

on the block diagram of an open loop control system, what is the following term to refers as the output

A

measured value

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6
Q

the error signal is the output of which component of a closed loops control system?

A

controller

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7
Q

what level of damping has a damping ratio equal to 1

A

Critically Damped

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8
Q

what level of damping would result in a response which quickly reaches the steady state value initially, but results in the response oscillating around the steady state for a significant period of time?

A

underdamped

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9
Q

how many oscillations will the response of an optimally damped system generally go through before entering the acceptance zone

A

1.5

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10
Q

what level of damping has a dampening ratio greater than 1

A

overdamped

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11
Q

what form of isolation barrier is required in an interlock when it is possible for two sets of contacts to touch each other back to back in the event of contact weld

A

Galvanic isolation

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12
Q

What type of electrical interlocking system is described as ‘the power source of the hazard is interrupted by the switching of a circuit which controls the power switching device

A

Control interlocking

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13
Q

what voltage will a 1st order system reach after one time constant if 10v is applied as the input

A

6.3

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14
Q

which of the following is a type of non-contact actuation interlock?

A

magnetic actuation

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15
Q

what transducer property is defined as ‘the variation of the transducers output around an expected value for a given constant input?

A

repeatability

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16
Q

in a negative temperature coefficient resistor, the resistance will have what response as the temperature increases?

A

linear decrease

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17
Q

when using an AC tachometer generator as an input to a servo system, an increase of what would be undesirable?

A

frequency

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18
Q

when using differential pressure to determine flow rates, what is used to create the difference in the pressure within the pipe?

A

orifice plate

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19
Q

what does An optical phenomenon in which the materials conductivity is increased when light is absorbed by the material describe

A

photoconductivity

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20
Q

What transducer property is defined as ‘how much the output changes for a change in input’?

A

Sensitivity

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21
Q

What would the fundamental interval of a PT100 RTD be if the resistance at a 100° C reads 138.50?

A

38.5

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22
Q

What would cause a decrease in the number of pulses generated by a phonic wheel transducer?

A

A increase in shaft rotation speed

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23
Q

What happens to the resistance of a LDR when the intensity of light is increased?

A

Decreases in a non-linear fashion

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24
Q

What transducer property is defined as ‘the output will always be considered to be equal to the input when 67% of the original error has been corrected’?

A

Response Time

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25
Q

what does CJCU stand for?

A

Cold junction compensating unit

26
Q

What is a Linvar used for?

A

To measure angular displacement

27
Q

What would happen to the output of a DC Tacho Generator if the speed is increased?

A

DC voltage level increases

28
Q

How can ships role be compensated for when using capacitive tank level transducers to measure the liquid level of a tank?

A

Use two or more level transducers

29
Q

What effect does a thermocouple use?

A

seebeck

30
Q

Which are the two categories that LDRs can be divided into based on the materials used in their construction?

A

Intrinsic and extrinsic

31
Q

How can the ripple produced by the commutator of a DC Tacho Generator be reduced?

A

Adding a low pass filter

32
Q

What form of friction is directly proportional to velocity?

A

Viscous

32
Q

What would happen to the sensing range of an ultra-sonic level sensor if the sensing frequency is increased?

A

The range would widen

33
Q

What would the maximum angle of the output shaft of a basic positional servo system reach if a 10° step was applied to the input shaft?

A

20°

34
Q

what does The loss of angular motion which occurs when the direction of rotation of a mechanical drive is reversed define

A

backlash

35
Q

What form of friction causes an initial drag that must be overcome before motion commences?

A

Static

36
Q

What does the phase advance circuit do in a servo system?

A

Modifies the error voltage, causing the driving current to reduce before 0o = 0i

37
Q

Which of the following terms is defined as ‘the maximum torque which can be applied to an energised stationary motor without causing spindle rotation’?

A

Holding tarque

38
Q

Which type of servo system stabilisation has the disadvantage of it being susceptible to electrical noise?

A

Phase advance

39
Q

Which of the following terms is defined as the number of steps per second applied sequentially to the field windings to cause motor rotation’?

A

Stepping rate

40
Q

What type of encoder accurately records change in position but does not power up with a fixed relationship between encoder state and physical shaft position?

A

Incremental

41
Q

What part of a 4-20mA current loop converts the sensor’s measurement into a current signal?

A

Transmitter

42
Q

What signal would be transmitted from a 4-20mA tank level sensor if the level in the tank was at 12.5% full?

A

6 mA

43
Q

How far would a stepper motor with a step angle of 12° travel if fed with 300 pulses?

A

10 rotations

44
Q

The ability for a 4-20mA control loop to work over long distances is a function of what fundamental law of electricity?

A

Ohm’s Law

45
Q

What signal would be transmitted from a 4-20mA tank level sensor if the level in the tank was at 37.5% full?

A

10 mA

46
Q

What would the step angle of a stepper motor be if it had 8 rotor teeth and 6 stator windings?

A

7.5

47
Q

How many components make up a 4-20mA current loop?

A

5

48
Q

What is the least amount of 4-20mA tank level sensors required to give both continuous level output and high and low level alarms?

A

1

49
Q

What error occurs when there is insufficient number of bits used when converting between analogue to digital?

A

bit error

50
Q

Which of the following elements would not be found incorporated into a microcontroller?

A

VDU

51
Q

What mode of transmission enables two or more communication channels to share the band width of a communication medium?

A

broadband

52
Q

Which DAC requires only two different sized resistors?

A

r2r ladder

53
Q

What type of network topology features a common backbone to connect all devices to?

A

star

54
Q

What mode of transmission has only one transmitting device and several receivers?

A

broadcast

55
Q

The useable frequency range of a copper cable is known by which of the following terms?

A

Bandwidth

56
Q

Bus networks work best with a limited number of devices, but at what percentage of network loading will likely result in performance problems caused by collisions?

A

Above 70%

57
Q

Whose theorem states that when converting between analogue to digital ‘the signal must be sampled at a frequency which is greater than twice the highest frequency component present in the signal’?

A

Nyquist/Shannon

58
Q

What would happen to the signal power of a copper cable if it was attenuated by 3 dB?

A

Decrease by 50%

59
Q

What form of data transmission will require each byte of data to contain a timing signal for the receiver to detect it?

A

Synchronous