Data Acquisition Flashcards
What are the four standard elements of a DAQ device? (A single answer is correct)
a. Analogue I/O, Digital I/O, Counters, Pulse Width Modulation.
b. Analogue I/O, Digital I/O, Counters, Frequency.
c. Analogue Output, Analogue Input, Digital I/O, Frequency.
d. Analogue Output, Analogue Input, Digital I/O, Counters.
d. Analogue Output, Analogue Input, Digital I/O, Counters.
Analogue and Digital I/O’s, and Counters (iterations).
From that you can then measure freq, pwm, period etc
Which of the Figures Q illustrate LabVIEW code to implement a Functional Global Variable? (A single answer is correct).
A, B, C, D
A
The general form of a function global variable includes an unitalicized shift register with a single iteration for or while loop.
So the only one with a perpetual loop with a stop button is A.
Which of the following statements about an optical quadrature encoder with 200 counts per revolution are correct? (More than one answer may be correct).
a. The resolution will be 0.45 deg.
b. The resolution will be 1.8 deg.
c. Differentiating the signal encoder output will produce a noiseless angular velocity signal.
d. The output of the encoder will be a digital signal
a. The resolution will be 0.45 deg.
c. Differentiating the signal encoder output will produce a noiseless angular velocity signal.
d. The output of the encoder will be a digital signal
a. 360 deg / 200cpr = 1.8 / 4 = 0.45 deg …divide by 4 as quadrature!
c. Will essentially smoothen it, think TV
d. Encoder can only output digital
Which of the following statements regarding optical encoders is correct? (A single answer is correct)
a. Optical encoders output a digital signal.
b. Optical encoders output an analogue signal.
c. Optical encoders utilise small magnets inside them to sense position.
d. Optical encoders always have a high resolution.
a. Optical encoders output a digital signal.
Which of the following statements about race conditions is correct? (A single answer is correct).
a. Race conditions are easy to identify and debug.
b. Most race conditions only occur when a resource has multiple writers.
c. You can avoid race conditions by using variables.
d. Code with race conditions behaves differently every time it is executed.
b. Most race conditions only occur when a resource has multiple writers.
Race conditions are difficult to identify and fix, only occur when multiple writers, they can be avoided by reducing variables and controlling shared resources.
What is the code width (resolution) of a 12-bit ADC with a voltage signal range of -5V to +5V. (A single answer is correct)
a. 1.2μV
b. 1.2mV
c. 0.42V
d. 2.4mV
d. 2.4mV
10V / 2^12 = 0.00244V = 2.4mV
Which of the following statements are correct regarding arrays. (More than one answer may be correct)
a. You can create an array of arrays.
b. You can have an array with more than 3 dimensions.
c. It is possible to have a 2D array of ‘string’ data type.
d. The first element in an array is indexed at 0.
b. You can have an array with more than 3 dimensions.
c. It is possible to have a 2D array of ‘string’ data type.
d. The first element in an array is indexed at 0.
No you can’t create an array of arrays, no shit 8x8 etc, yes string=words, indexed at 0.
Which of the following statements regarding variables are correct? (More than a single answer may be correct)
a. Variables can be the following types: Local, Global, Functional Global and Shared.
b. Variables allow you to circumvent normal dataflow by passing data from one place to another without connecting the two places with a wire.
c. Variables should only be used when absolutely necessary.
d. You should use a global variable or a single process shared variable to share data between multiple VI’s.
a. Variables can be the following types: Local, Global, Functional Global and Shared.
b. Variables allow you to circumvent normal dataflow by passing data from one place to another without connecting the two places with a wire.
c. Variables should only be used when absolutely necessary.
d. You should use a global variable or a single process shared variable to share data between multiple VI’s.
All are correct
Which of the following statements are correct? (More than one answer may be correct).
a. The speed which a While loop executes can be changed.
b. A For loop can have an iteration terminal.
c. You cannot have a While loop within a While loop.
d. A While loop can execute zero times.
a. The speed which a While loop executes can be changed.
b. A For loop can have an iteration terminal.
Inspect the LabVIEW code and identify which of the statements a) – d) are correct. (More than a single answer may be correct)
a. The top loop will execute 3 times
b. The loops will not execute in parallel
c. The output of ‘Numeric’ will be 2
d. Neither of the loops will execute
a. The top loop will execute 3 times
b. The loops will not execute in parallel
c. The output of ‘Numeric’ will be 2
Top executes 3 times yes. Not parallel, think electricity, this would be series not parallel. And numeric will be 2 as iterations is 0 based.
Which of the following statements are correct? (More than one answer may be correct)
a. The 4 bit binary number 0101 represents the number 5.
b. The 4 bit binary number 0111 represents the number 10.
c. The highest numeric value that can be represented by a 12-bit number is 4095?
d. The highest numeric value that can be represented by a 12-bit number is 4096?
a. The 4 bit binary number 0101 represents the number 5.
c. The highest numeric value that can be represented by a 12-bit number is 4095
0x2^3 + 12^2 +02^1 + 1*2^0
= 4 + 1 = 5
b^n -1
= 2^12 -1 = 4095
Which of the following statements are correct? (More than one answer may be correct)
a. To reduce problems associated with aliasing you should apply a low pass filter at half the sampling frequency.
b. Aliasing can always be solved by increasing the sampling frequency.
c. Aliasing means frequencies above half of the sampling frequency appear at frequencies below half the sampling frequency.
d. To avoid problems with aliasing your sampling frequency should be twice that of the highest frequency contained in your signal.
a. To reduce problems associated with aliasing you should apply a low pass filter at half the sampling frequency.
c. Aliasing means frequencies above half of the sampling frequency appear at frequencies below half the sampling frequency.
d. To avoid problems with aliasing your sampling frequency, the frequency should be twice that of the highest frequency contained in your signal.
For b. It doesn’t solve anything. Frequencies above half will still appear below. Aliasing doesn’t disappear.
Which of the following statements is correct about buffered Data Acquisition? (A single answer is correct)
a. Buffered Data Acquisition does not require a fixed sample rate.
b. Buffered Data Acquisition is not suitable for control applications.
c. Buffered Data Acquisition utilises less memory overhead than single sample Data Acquisition.
d. Buffered Data Acquisition should always be used for acquiring Digital Signals.
b. Buffered Data Acquisition is not suitable for control applications.
Buffered does require a fixed sample rate, isn’t suitable for control applications, uses more memory (think RAM), just not true.
Which of the statements below is correct regarding the LabVIEW code illustrated in the figure? (More than one answer may be correct)
a. The Case structure only has the Cases ‘Startup’, ’Shutdown’, and ’Idle’.
b. The error cluster has data types of Boolean, Numeric, and String contained within it.
c. This is an example of a state machine architecture.
d. The code within the “Startup” Case will execute as fast as possible.
b. The error cluster has data types of Boolean, Numeric, and String contained within it.
c. This is an example of a state machine architecture.
d. The code within the “Startup” Case will execute as fast as possible.
a. No as we don’t know for sure that its only startup, shutdown and idle. Could be more.
b. Yes as all error clusters contain status (boolean), code that identifies the error numerically, and source (string).
c. Yes state machine as we have T/F, numbers (iterations, wait timer) and text.
d. Yes as no timer.
The equation below illustrates the relationship between the Gain in decibels and the gain of an amplifier. Which of the following answers (a-d) correctly represents the gain in dB if a voltage of 400μV is the input to the amplifier and a voltage of 5mV is measured as the output. The answers are displayed in 2 significant figures format. (A single answer is correct). GdB = 20 Log(G) a. 61.6 dB b. -61.6 dB c. 21.9 dB d. -21.9 dB
Input = 400 x 10-6V. Output = 5 x 10-3V
G = 5 x 10-3 / 400 x 10-6 G = 0.005 / 0.0004 G = 12.5
Gdb = 20Log10G Gdb = 20Log10 12.5 Gdb = 20 x 1.0969 Gdb = 21.9
Which of the following statements about ultrasonic sensors are correct? (More than one answer may be correct)
a. Ultrasonic sensors use ultrasound at a frequency of 2KHz.
b. Two ultrasonic sensors can interfere with each other.
c. The bearing of the ultrasonic sensor will have a finite uncertainty.
d. Environmental noise cannot affect an ultrasonic sensor.
b. Two ultrasonic sensors can interfere with each other.
c. The bearing of the ultrasonic sensor will have a finite uncertainty.
50KHz not 2KHz, ofc they can interfere, won’t be infinitely uncertain, environmental noise can affect ultrasonic…imagine a dolphin and a container ship
The LabVIEW code illustrates a For Loop and Shift Register. What will be the number displayed in the numeric indicator ‘Output’ when the code has finished executing? (A single answer is correct).
a. 4
b. 24
c. 8
d. 2
a. 4
Top shift register: 2x1 = 2 2x2 = 4 2x3 = 6 2x4 = 8
Bottom shift registers means previously value. So, 2 initial 2 initial from above 2 = 2x1 4 = 2x2
Whilst top does, 2x1, 2x2, 4x3, 12x4
The LabVIEW code illustrates a For loop. What will be the output of ‘Indicator’ when the loop finishes? (A single answer is correct)
a. 27
b. 19
c. 0
d. 6
c. 0
Value will always be 0
A Data Acquisition system has been developed to monitor the deflection of an aircraft wing for a dynamic test. Sensors are placed on the wing and 10m of cabling is used to pass the sensor signals to a central Data Acquisition (DAQ) system. The signals of interest are under 30Hz and there is a problem with high frequency noise in the measurements. Which of the following solutions could solve the problem? (More than a single answer may be correct)
a. Applying a high pass filter to the sensor signals before they reach the DAQ system.
b. Applying a low pass filter to the sensor signals before they reach the DAQ system.
c. Applying an amplifier to the sensor signal before sending through the cabling.
d. Applying a second order Butterworth filter with a cut off frequency of 40Hz.
b. Applying a low pass filter to the sensor signals before they reach the DAQ system.
c. Applying an amplifier to the sensor signal before sending through the cabling.
d. Applying a second order Butterworth filter with a cut off frequency of 40Hz.
Everything but high-pass. For Butterworth just read it. It cuts off anything above 40Hz (45Hz is half above sample). Hence, does the same job as a low pass filter.
Inspect the LabVIEW code in the figure and identify which of the following statements is correct? (A single answer is correct).
a. The number of loop iterations will be 7.
b. The number of loop iterations will be 3.
c. The code will not execute.
d. The indicator “Iterations” will display a value of 3 after code has finished.
b. The number of loop iterations will be 3.
Loop will iterate 3 times as the 3 element array is auto indexed (brackets not block). And hence, can only have 3 elements and not a 4th so will stop.
Which of the following statements are correct? (More than one answer may be correct)
a. To reduce problems associated with aliasing you should apply a low pass filter at two times the sampling frequency.
b. Aliasing means that frequencies at greater than half the sampling frequency will appear as frequencies below half the sampling frequency.
c. The passband ripple for a filter is undesirable as this will result in changes in the magnitude of frequencies in the retained frequency domain.
d. The stopband ripple for a filter is undesirable as this will result in frequencies outside the frequency range of interest retaining some finite magnitude.
b. Aliasing means that frequencies at greater than half the sampling frequency will appear as frequencies below half the sampling frequency.
c. The passband ripple for a filter is undesirable as this will result in changes in the magnitude of frequencies in the retained frequency domain.
d. The stopband ripple for a filter is undesirable as this will result in frequencies outside the frequency range of interest retaining some finite magnitude.
Yes low-pass filter but not a 2x the sample frequency, b is the definition, we know all other filters are undesirable bar the low-pass filter.
Which of the following statements about arrays and clusters are correct? (More than one answer may be correct)
a. Arrays do not have to be a fixed size
b. You can not have an array of arrays
c. A cluster cannot contain boolean data
d. Clusters can contain more than one data type
a. Arrays do not have to be a fixed size
b. You can not have an array of arrays
d. Clusters can contain more than one data type
Arrays can be whatever size, correct you can’t have arrays of arrays, a cluster can contain boolean, clusters can contain 3 types of data
Note: A cluster is basically an array bundled with criteria. I.e. a list of students who graduated with their age. 3 criteria, string, boolean, numeric
The musical note middle c is an oscillation at 262Hz. To accurately represent the waveform in the time domain, which sampling frequency would be most suitable? (A single answer is correct)
a. 131 Hz
b. 262 Hz
c. 524 Hz
d. 2620 Hz
d. 2620 Hz
262 Hz in 0.1s, hence 262/0.1 = 2620Hz
Inspect the LabVIEW code. Which of the statements a) – d) are correct? (More than a single answer may be correct)
a. The Indicator will display a value of 4.5 when the loop finishes executing.
b. The Indicator will display a value of 1.5 when the loop finishes executing.
c. If the DBL precision conversion block was not utilised and the integer number was connected to the divide block, there would be an error and code would not execute.
d. The loop will execute two times.
a. The Indicator will display a value of 4.5 when the loop finishes executing.
d. The loop will execute two times.
9/1 = 9
9/2 = 4.5
Stop as 2 iterations
The equation illustrates the relationship between the Gain in decibels and the gain of an amplifier. Which of the following answers (a-d) correctly represents the gain in dB if a voltage of 100μV is the input to the amplifier and a voltage of 5V is measured as the output. The answers are displayed in 2 decimal places format. (A single answer is correct). GdB = 20 Log(G) a. -93.98 dB b. 93.98 dB c. 33.98 dB d. -33.98 dB
b. 93.98 dB
100μV = 0.1mV = 0.0001V 20 log(5/0.0001) = 93.98dB
The LabVIEW code illustrates a While loop. What frequency will the loop operate at? (A single answer is correct)
a. 100Hz
b. 10Hz
c. 1000Hz
d. 50Hz
a. 100Hz
Loop executes every 10ms. 10ms occurs 100x in 1s. Hence, 100Hz.
What is the code width (resolution) of a 16-bit ADC with a voltage signal range of 0V to +10V. (A single answer is correct)
a. 0.625mV
b. 15mV
c. 0.625V
d. 0.15mV
d. 0.15mV
10 / 2^16 = 0.15mV
Inspect the LabVIEW code which illustrates a calculator with two functions ‘add’ and ‘subtract’. Identify which of the statements a) – d) are correct. (More than one answer may be correct)
a. The structure inside the while loop is a case structure.
b. The value displayed in indicator will depend on the value selected in the control.
c. The loop will continue to complete calculations so long as the stop button has a value of false selected.
d. This .vi architecture is easy to adjust to include multiply and divide functions.
All are correct. Says only a and d, but b and c are defo right also.
Buffered I/O should be used when? (More than a single answer may be correct)
a. Many samples are acquired at a faster rate than can be displayed
b. The sampling rate must be precise
c. The sample rate needs to be variable
d. Trying to control an external system
a. Many samples are acquired at a faster rate than can be displayed
b. The sampling rate must be precise
Use buffered I/O when:
- Many samples are acquired at a rate faster than is practical to display, store, or analyze in real-time
- Data is acquired/displayed continuously on the fly
- The sampling period must be precise and uniform throughout the data samples
Which of the following statements are true? (More than a single answer may be correct)
a. The accuracy of a system is always equal to its resolution
b. The accuracy of the sensor is the maximum difference that will exist between the actual value and the indicated value at the output of the sensor.
c. The resolution of a system is the smallest increment it can measure
d. The resolution of a system can never be more than 3 times its accuracy
b. The accuracy of the sensor is the maximum difference that will exist between the actual value and the indicated value at the output of the sensor.
c. The resolution of a system is the smallest increment it can measure
Resolution = x dp Accuracy = +- x
Which of the following statements describes the concept of race conditions in LabVIEW programming? (A single answer is correct).
a. A situation in which two sub .vi’s are trying to execute a task quicker than each other.
b. A situation where the timing of events or the scheduling of tasks may unintentionally affect an output or data value.
c. A situation in which a cluster has to move data between two locations in the fastest possible time.
d. A situation in which you are trying to save data to an array before a timed loop begins its next iteration.
b. A situation where the timing of events or the scheduling of tasks may unintentionally affect an output or data value.
The definition^
Inspect the LabVIEW code in Figure Q3. If this program is run multiple times, what will the value on ‘Indicator 1’ be? (A single answer is correct)
a. 2
b. 3
c. 6
d. Cannot say
d. Cannot say
We don’t know as there is no initial value at the shift register
Which of the following statements are correct regarding sequence structures, as illustrated. (More than one answer may be correct)
a. Sequence structures are not an efficient way to program if we may need to change the order in which the sequences are to execute.
b. The sequence frames will execute Left to Right.
c. You can stop a sequence structure part way through its execution.
d. You cannot pass data between frames in the sequence structure.
a. Sequence structures are not an efficient way to program if we may need to change the order in which the sequences are to execute.
b. The sequence frames will execute Left to Right.
You cannot stop part way through and you can pass data between frames
Inspect the LabVIEW code. Which of the statements a) – d) are correct? (More than a single answer may be correct)
a. The top loop will execute at 10 times the rate of the bottom loop
b. Indicator 1 will count upwards in increments of 0.1 starting at 0.
c. Indicator 2 will count upwards in increments of 1 starting at 0.
d. This code illustrates how you can program in parallel with LabVIEW.
b. Indicator 1 will count upwards in increments of 0.1 starting at 0.
d. This code illustrates how you can program in parallel with LabVIEW.
a. Is obviously wrong.
c. Is wrong because CONTINUE IF TRUE SYMBOL. Hence false constant means that the bottom loop will run only once and output 0.
What are the four standard elements of a DAQ device? (A single answer is correct)
a. Analogue I/O, Digital I/O, Counters, Pulse Width Modulation
b. Analogue Output, Analogue Input, Digital I/O, Counters
c. Analogue I/O, Digital I/O, Counters, Frequency
d. Analogue Output, Analogue Input, Digital I/O, Frequency
b. Analogue Output, Analogue Input, Digital I/O, Counters
Duplicate with card 1.
Which of the following statements about sensors are correct? (More than one answer may be correct)
a. Fibre optic strain gauges are a good choice when there are high levels of background electro-magnetic interference.
b. Three important factors when choosing a sensor are environmental factors, economic factors and sensor characteristics.
c. A single channel optical encoder with 200 gratings will have a resolution of 1.8deg.
d. The output of an optical encoder is an analogue signal.
a. Fibre optic strain gauges are a good choice when there are high levels of background electro-magnetic interference.
b. Three important factors when choosing a sensor are environmental factors, economic factors and sensor characteristics.
c. A single channel optical encoder with 200 gratings will have a resolution of 1.8deg.
Fibre optic gauges are immune to EM, yes, 360deg/200 = 1.8deg, encoder always outputs digital.
Inspect the LabVIEW code and identify which of the statements a) – d) are correct. (More than one answer may be correct)
a. The top loop will execute 2 times.
b. The loops will execute in parallel.
c. Both loops will stop at the same time
d. Indicator and Indicator 2 will display the same value when the programme finishes executing.
a. The top loop will execute 2 times.
d. Indicator and Indicator 2 will display the same value when the programme finishes executing.
Not parallel as they’re connected, hence it flows. Also the 1st loop will stop before the 2nd as not parallel. Imagine it was electrical, it would be series as wire connecting.
Inspect the LabVIEW code. Identify which of the statements a) – d) are correct. (A single answer is correct)
a. The loop will execute 5 times.
b. The values inserted into ‘Output Array’ will be the iteration terminal value multiplied by 2.
c. The size of the ‘Output Array’ can be increased by increasing the numeric value wired to N.
d. Any values in ‘3 element Array’ (outside the For loop) will be overwritten by the code.
a. The loop will execute 5 times.
So essentially every value gets inserted but then deleted as NO shift register. So every value gets overwritten outside the loop and the output array will be identical to the input array.
Technically, the 5th/last value would have been inserted into the array but its 5th element in a 3 element array hence ignored.
a. Yes iterates 5 times.
b. Wrong because no shift register
c. No its a 3 element array.
d. No. The code won’t write any values as explained above.
Which of the following statements are correct? (More than one answer may be correct)
a. The 6 bit binary number 000011 represents the decimal number 3.
b. The highest number that can be represented using a 6-bit representation is 64.
c. Sensors which utilize digital signals as outputs are less susceptible to low voltage noise induced in the transmission wiring.
d. Multiplexers can be utilized in DAQ systems to reduce the cost.
a. The 6 bit binary number 000011 represents the decimal number 3.
c. Sensors which utilize digital signals as outputs are less susceptible to low voltage noise induced in the transmission wiring.
d. Multiplexers can be utilized in DAQ systems to reduce the cost.
a. 0… + 12^1 + 12^0 = 2+1 = 3
b. 2^6 -1 = 63 not 64
c. 1’s and 0’s vs physical analogue? So digital signals are far more immune to interference.
d. Multiplexing involves routing a number of signals into a single digitizer. This is a much more cost effective way of expanding the signal count of the system. Multiplexing is necessary for any high channel count application.
Inspect the LabVIEW code. Which of the answers a) – d) correctly states the value displayed by the indicator when the code has finished executing? (A single answer is correct).
a. 8
b. 9
c. 4
d. 7
b. 9
1+2+1+1=5
5+2+1+1=9
Key is that the shift registers are baso trickle down. So top gets 5, mid[1], bottom[2]. Hence, mid and bottom both stay on the initial value of 1.
The LabVIEW code illustrates a While loop. Which of the following statement are correct? (More than one answer may be correct).
a. The For Loop will execute 3 times.
b. When the loop has completed the iteration terminal will have a value of 2 associated with it.
c. Given the input to the or gate, it serves little function and could be removed without effecting the codes functionality.
d. The For Loop will execute 2 times.
b. When the loop has completed the iteration terminal will have a value of 2 associated with it.
c. Given the input to the or gate, it serves little function and could be removed without effecting the codes functionality.
This is a while loop. not a for loop. A for loop is like a pad of paper with a corner folded over.
0>1 false, 1>1 false, 2>1 true so stop. 3 iterations so value shows 2 (indexed). And yes the or gate is pointless and makes no sense.
Which of the following statements are correct? (More than one answer may be correct).
a. A While Loop must execute at least once
b. Unlike a While Loop a For Loop cannot have a conditional terminal
c. You can have a While Loop within a While Loop.
d. A While Loop iteration terminal is zero indexed
a. A While Loop must execute at least once
c. You can have a While Loop within a While Loop.
d. A While Loop iteration terminal is zero indexed
Both can have stop buttons, i.e. conditional terminals.
Which of the following statements are correct regarding arrays and clusters? (More than one answer may be correct)
a. You can create an array of arrays.
b. You can have an array with more than 5 dimensions.
c. You can have a cluster with multiple data types within it
d. You can have an array with multiple data types within it
b. You can have an array with more than 5 dimensions.
c. You can have a cluster with multiple data types within it
Bool, string, numerical in clusters…but not arrays. Think a cluster of data types.
What is the resolution (code width) of a 24-bit ADC with a voltage signal range of 0V to +10V? (A single answer is correct)
a. 0.732mV
b. 0.596μV
c. 6.0V
d. 0.852nV
b. 0.596μV
10V / 2^24 = 0.596μV
Inspect the LabVIEW code. Which of the following statements are correct? (More than one answer may be correct).
a. The loop will execute 20 times
b. ‘Waveform Graph’ will display 20 random numbers
c. ‘Waveform Graph’ will only display data after the loop has finished
d. The figure illustrates a For Loop
a. The loop will execute 20 times
b. ‘Waveform Graph’ will display 20 random numbers
c. ‘Waveform Graph’ will only display data after the loop has finished
d. The figure illustrates a For Loop
All are correct. Waveform graph is outside the loop and has auto indexing tunnel. Hence, it will plot once the loop has finished and sends the data outside the loop. A for loop is the pad of paper with a corner folded.
Which of the following statements are correct? (More than one answer may be correct).
a. Hysteresis means the output will not be dependent on its recent previous states
b. Buffered Data Acquisition requires a fixed sample rate.
c. A control system will be unreliable using a Buffered Data Acquisition approach.
d. Timing functions provide the processor with time to complete other tasks
b. Buffered Data Acquisition requires a fixed sample rate.
c. A control system will be unreliable using a Buffered Data Acquisition approach.
d. Timing functions provide the processor with time to complete other tasks
Hysteresis is dependent on its previous state. Buffered Data Acquisition needs a fixed sample rate and isn’t suitable for control applications. Timing functions do allow time. Think…while waiting it will still do other tasks in the code elsewhere if running parallel.
Which of the following statements are correct? (More than one answer may be correct)
a. A multiplexer is used to route a number of signals into a single digitiser
b. In general, a sensor with a digital output will be less susceptible to noise than a sensor with an analogue output
c. Sensors utilizing modulated infrared signals can detect a signal even if the strength is low.
d. Intensity based infrared sensors are susceptible to problems caused by ambient light levels
a. A multiplexer is used to route a number of signals into a single digitiser
b. In general, a sensor with a digital output will be less susceptible to noise than a sensor with an analogue output
c. Sensors utilizing modulated infrared signals can detect a signal even if the strength is low.
d. Intensity based infrared sensors are susceptible to problems caused by ambient light levels
All are correct.
An ultrasonic sensor emits a pulse of 50KHz sound which travels to an object and returns back to the sensor after 100ms. How far is the sensor from object? You should assume the medium the sound travels through is air. (A single answer is correct)
a. 17m
b. 34m
c. 72m
d. 30m
a. 17m
Sound travels at 340m/s. Hence, 100ms = 0.1s x 340m/s = 34m
34m and 100ms is round trip there and back.
Hence, /2 = 17m
Inspect the LabVIEW code. When the loop has finished what will be the value in ‘Shift Register Answer’? (A single answer is correct)
a. 4
b. 16
c. 64
d. 32
d. 32
1x2=2, 2x2=4, 4x2=8, 8x2=16, 16x2=32
Baso, 2^5 = 32
Which of the following statements are correct regarding concepts of measurement? (A single answer is correct)
a. Hysteresis means the output will be dependent on its recent previous states
b. The relationship between input and output of a linear system can always expressed by a polynomial expression.
c. Accuracy and precision are the same concept.
d. The resolution of a system is the same as its accuracy.
a. Hysteresis means the output will be dependent on its recent previous states
^^^Definition
Inspect the LabVIEW code. If this program is run two times, what will the value of ‘Output’ be? You should assume the program has never run before. (A single answer is correct)
a. 13
b. 7
c. 6
d. 12
d. 12
Not initialized shift register, therefore uses 0 or last value. Ran twice doesn’t mean iterations!
1st Run 2nd Run
0+3=3 6+3=9
3+3=6 9+3=12
Inspect the LabVIEW code and identify which of the following statements are correct. (More than one answer may be correct).
a. Only the first value from ’15 element array’ will be passed into the For Loop.
b. The For Loop will execute 10 times.
c. ‘Iterations’ will display a value of 4 when the for loop completes.
d. Data will only leave the For Loop once it has executed.
c. ‘Iterations’ will display a value of 4 when the for loop completes.
d. Data will only leave the For Loop once it has executed.
5 element array, hence 5 iterations, which will be displayed as 4.
Which of the following statements about Aliasing are correct? (More than a single answer may be correct)
a. Aliasing is caused when a signal is over sampled
b. Aliasing is caused by a sampling rate which is too low for the frequencies being measured
c. The Nyquist theorem states that when an analogue signal is sampled any signal components at frequencies greater than one-half the sampling frequency appear in the sampled data as a lower frequency signal
d. Aliasing can be avoided by removing signal components above one half of the sampling frequency
b. Aliasing is caused by a sampling rate which is too low for the frequencies being measured
c. The Nyquist theorem states that when an analogue signal is sampled any signal components at frequencies greater than one-half the sampling frequency appear in the sampled data as a lower frequency signal
d. Aliasing can be avoided by removing signal components above one half of the sampling frequency
Aliasing arises when a signal is UNDER sampled
Which of the following statements is correct regarding Input/output cards? (A single answer is correct)
a. Most input/output cards are 32bit
b. Windows based Data Acquisition systems are always deterministic
c. General purpose input/output cards only have digital signals
d. The accuracy of an input/output card is dependent on the bit length e.g. 12bit, 16bit
d. The accuracy of an input/output card is dependent on the bit length e.g. 12bit, 16bit
I think the most common is like 12 bit. A deterministic system is a system in which no randomness is involved in the development of future states of the system, so windows systems can be random basically. Can be both analogue and digital. Yes accuracy is related to the bit length.
Which of the following statements are correct? (More than one answer may be correct).
a. Fibre optic strain gauges are immune to electro-magnetic noise.
b. Modulated infra-red sensors are more susceptible to variations in background electro-magnetic radiation than intensity-based ones.
c. Quadrature rotary encoders can be used to determine the direction of rotation.
d. Choosing a sensor involves consideration of environmental, economic, and sensor characteristics.
a. Fibre optic strain gauges are immune to electro-magnetic noise.
c. Quadrature rotary encoders can be used to determine the direction of rotation.
d. Choosing a sensor involves consideration of environmental, economic, and sensor characteristics.
Modulated IR sensors are less susceptible to external interference. Quadrature rotary encoders can be used as they have 2 channels (2 sensors and 2 receivers).
Which of the following statements are correct regarding filtering? (More than one answer may be correct).
a. Filters can be utilized to remove both high frequency and low frequency signals
b. Stopband ripple is undesirable
c. An ideal filter will have a sharp transition
d. Passband ripple is undesirable
a. Filters can be utilized to remove both high frequency and low frequency signals
b. Stopband ripple is undesirable
c. An ideal filter will have a sharp transition
d. Passband ripple is undesirable
High-pass can remove lows, and low-pass can remove highs. Think high-pass = let the highs pass through.
Ripples are undesirable and caused by poorly designed filters.
An ideal filter will have a flat response where the desired signal is not altered. Then a sharp transition to reduce unwanted frequencies.
Which of the following statements is correct? (A single answer is correct)
a. The accuracy of a system is always expressed as an absolute value
b. Random error always has the same magnitude
c. When a measurement system is calibrated there is zero bias error
d. The positive and negative range of sensor are always equal in magnitude
c. When a measurement system is calibrated there is zero bias error
No accuracy is +- x, so not absolute. Random errors can be different sizes every time they occur. Imperfect calibration is a cause of bias error, hence calibrate means no bias error. +ve and -ve ranges can be different sizes.
Inspect the LabVIEW code and identify which of the following statements are correct. (More than one answer may be correct).
a. ‘indicator’ will display the time taken for the last loop to execute.
b. ‘indicator’ will always display a value of 50ms.
c. If ‘Stop Button’ has a value of false the loop will continue.
d. Each time the loop executes the value in the left hand side shift register terminal will be the value that was sent to the right hand side shift register terminal in the previous loop iteration.
a. ‘indicator’ will display the time taken for the last loop to execute.
c. If ‘Stop Button’ has a value of false the loop will continue.
d. Each time the loop executes the value in the left hand side shift register terminal will be the value that was sent to the right hand side shift register terminal in the previous loop iteration
Will show the time taken for the most recent loop, not necessarily 50ms as it still has to execute after that, so more likely 50ms + a few ms. Its an infinite loop until stop=true as there are no set number of iterations. Yes that is how shift registers work.
Which of the following statements is correct about the LabVIEW code? (A single answer is correct)
a. The LabVIEW code contains a While Loop
b. The code contains a coercion dot which may affect the speed at which the code can execute.
c. The LabVIEW code generates a random number every 1000 seconds
d. In total 100 random numbers will be generated within the loop
d. In total 100 random numbers will be generated within the loop
Pad of paper with a corner folded is a for loop. Coercion dots are used when LabVIEW has converted data/values into a different representation. That symbol means wait until next multiple, so the loop will run every multiple of 1000ms. So its baso the same unless the loop starts at a weird time, so 57ms into the code if that makes sense.
The LabVIEW code illustrates two parallel While loops. Which of the following statements are correct? (More than a single answer may be correct)
a. When ‘Loop Control’ is pressed both loops will stop
b. Once the .vi begins Loop 2 will execute only once
c. The loops are programmed to execute at different frequencies
d. The first data point on ‘Chart 1’ will have a magnitude of zero
b. Once the .vi begins Loop 2 will execute only once
c. The loops are programmed to execute at different frequencies
d. The first data point on ‘Chart 1’ will have a magnitude of zero
a and b. If the loop control is pressed and true. It will stop loop 1, be outputted and enter loop 2. Loop 2 will execute just once and then stop.
c. Yes as iterations constantly increasing
d. Yes as sin(0) = 0
The LabVIEW code below illustrates a For loop. How many times does the loop execute and what will be the output of indicator ‘iteration terminal output’
a. The For loop will run 3 times. The output of indicator ‘iteration terminal output’ will be 1, 2, 3.
b. The For loop will run 2 times. The output of indicator ‘iteration terminal output’ will be 0, 1.
c. The For loop will run 2 times. The output of indicator ‘iteration terminal output’ will be 1, 2.
d. The For loop will run 3 times. The output of indicator ‘iteration terminal output’ will be 0, 1, 2.
b. The For loop will run 2 times. The output of indicator ‘iteration terminal output’ will be 0, 1.
Match the correct answer to each of the statements below
Items pink in colour on the block diagram indicate the data type is…
Items orange in colour on the block diagram indicate the data type is…
Items green in colour on the block diagram indicate the data type is…
Numeric, String, Boolean
Pink = String Orange = Numeric Green = Boolean
The LabVIEW code below illustrates a While loop. How many times does the loop execute and what is the highest value the iteration terminal will output?
a. The While loop will run 3 times. The highest value the iteration terminal will indicate is 2.
b. The While loop will run 2 times. The highest value the iteration terminal will indicate is 1.
c. The While loop will run 2 times. The highest value the iteration terminal will indicate is 2.
d. The While loop will run 3 times. The highest value the iteration terminal will indicate is 3.
a. The While loop will run 3 times. The highest value the iteration terminal will indicate is 2.
Identify where the condition terminal is in this while loop?
The stop button is the condition terminal. I.e. it is dependent on a condition.
An I8 numeric can represent how many different values?
2^8 = 256 values. Not 255, that is the highest number possible as 0 included.
Which of the following statements are correct regarding while loops? More than one answer may be correct.
a. While loops can execute zero times
b. While loops must execute at least once
c. While loops have a conditional terminal
d. While loops can theoretically run infinitely
b. While loops must execute at least once
c. While loops have a conditional terminal
d. While loops can theoretically run infinitely
While loops must execute more than once, and can run for as long as the while is true.
Which of the following statements are correct regarding For loops? More than one answer may be correct.
a. For loops can execute zero times
b. For loops always execute a fixed number of times
c. For loops can have a conditional terminal
d. For loops can theoretically run infinitely
a. For loops can execute zero times
c. For loops can have a conditional terminal
For loops have to have a set number of iteration given outside the loop, however if condition is met they can stop early.
Which of the following statements is correct about buffered Data Acquisition? (A single answer is correct)
a. Buffered Data Acquisition requires a fixed sample rate.
b. Buffered Data Acquisition requires a variable sample rate.
c. Buffered Data Acquisition utilises less memory overhead than single sample Data Acquisition.
d. Buffered Data Acquisition should always be used for acquiring Digital Signals.
a. Buffered Data Acquisition requires a fixed sample rate.
The LabVIEW code illustrates a For loop. What will be the output of ‘indicator’ when the loop finishes?
a. The output of ‘indicator’ when the loop finishes will be 7.
b. The output of ‘indicator’ when the loop finishes will be 6.
c. The output of ‘indicator’ when the loop finishes will be 8.
d. The output of ‘indicator’ when the loop finishes will be 10.
c. The output of ‘indicator’ when the loop finishes will be 8.
Which of the following statements regarding Field Programmable Gate Array (FPGA) are correct? (More than one answer may be correct)
a. DAQ systems with an FPGA can achieve superior performance.
b. DAQ systems with an FPGA are less deterministic.
c. DAQ systems with an FPGA are more deterministic.
d. FPGA’s are utilised in all DAQ systems.
a. DAQ systems with an FPGA can achieve superior performance.
c. DAQ systems with an FPGA are more deterministic.
Which of the following statements about timing functions are correct? (More than one answer may be correct)
a. A wait function inside a loop allows the .vi to sleep for a set amount of time.
b. Timing functions control the frequency that a loop executes.
c. Timing functions provide the processor with time to complete other tasks
d. Timing functions cannot be used inside case structures
a. A wait function inside a loop allows the .vi to sleep for a set amount of time.
b. Timing functions control the frequency that a loop executes.
c. Timing functions provide the processor with time to complete other tasks
Timing functions can be used in case structures hence false. But they can cause problems and hence should be avoided.
Inspect the figure and identify which of the statements a) – d) is correct. (A single statement is correct)
a. Represents neither Accuracy nor Precision.
b. Represents Resolution and Precision.
c. Represents Accuracy without Precision.
d. Represents Resolution without Precision.
c. Represents Accuracy without Precision.
Which of the statements a) – d) are correct regarding the concept of Hysteresis. (more than one answer may be correct)
a. Hysteresis means that the change in a parameter is dependent on its previous state.
b. Hysteresis means that the change in a parameter is independent of its previous state.
c. A DAQ system with a low level of Hysteresis is desirable.
d. A DAQ system with a high level of Hysteresis is desirable.
a. Hysteresis means that the change in a parameter is dependent on its previous state.
c. A DAQ system with a low level of Hysteresis is desirable.
Which of the following can be an input data type for a case structure? (more than one answer may be correct)
a. Boolean.
b. String.
c. Numeric.
d. Enum.
All correct.
Which of the following statements about Analogue to Digital Convertors (ADC’s) and Digital to Analogue Convertors (DAC’s) are correct? (more than one answer may be correct)
a. DAC’s are optimised for resolution and sampling rate.
b. ADC’s are needed for DAQ systems that utilise Personal Computers.
c. An analogue signal which is passed to an ADC and then to a DAC will be unaltered in comparison to the original signal.
d. ADC’s are optimised for either resolution or sampling rate.
b. ADC’s are needed for DAQ systems that utilise Personal Computers.
d. ADC’s are optimised for either resolution or sampling rate.
Inspect the LabVIEW code. Which of the statements a) – d) are correct? (More than a single answer may be correct)
a. The indicator will display a value of 4.5 when the loop finishes executing.
b. The Indicator will display a value of 1.5 when the loop finishes executing.
c. If the DBL precision conversion block was not utilised and the integer number was connected to the divide block, there would be an error and code would not execute.
d. The loop will execute two times.
a. The indicator will display a value of 4.5 when the loop finishes executing.
d. The loop will execute two times.
Which of the following statements are correct regarding sequence structures, as illustrated . More than one answer may be correct.
a. Sequence structures are not an efficient way to program if we may need to change the order in which the sequences are to execute.
b. The sequence frames will execute right to left.
c. You cannot stop a sequence structure part way through its execution.
d. The sequence frames will execute left to right.
a. Sequence structures are not an efficient way to program if we may need to change the order in which the sequences are to execute.
c. You cannot stop a sequence structure part way through its execution.
d. The sequence frames will execute left to right.
Which one of the following statements regarding clusters is correct?
a. Clusters can contain an Array of Boolean values.
d. Clusters can have both Controls and Indicators within them.
c. Clusters cannot contain Numeric Controls.
d. Clusters are used to save the allocation of memory in an application.
a. Clusters can contain an Array of Boolean values.
Identify which one of the following statements most accurately describes the advantage of utilising the cluster function ‘Unbundle by name’ as opposed to ‘unbundle’ in LabVIEW. The figure illustrates the cluster functions.
a. Unbundle by name enables data to be transferred quicker between locations.
b. Unbundle by name is more efficient with respect to memory usage.
c. Unbundle by name can be used with a wider variety of data types.
d. Unbundle by name enables an easier interpretation of the data within the cluster as each cluster element has an associated name.
d. Unbundle by name enables an easier interpretation of the data within the cluster as each cluster element has an associated name.
Which of the following statements are correct regarding arrays. More than one answer may be correct.
a. You can create an array of arrays.
b. You can have an array with more than 3 dimensions.
c. It is possible to have a 2D array of ‘string’ data type.
d. The first element in an array is indexed at 0.
b. You can have an array with more than 3 dimensions.
c. It is possible to have a 2D array of ‘string’ data type.
d. The first element in an array is indexed at 0.
Which of the following statements about arrays and clusters are correct? (More than one answer may be correct)
a. Arrays do not have to be a fixed size
b. You cannot have an array of arrays
c. A cluster cannot contain boolean data
d. Clusters can contain more than one data type
a. Arrays do not have to be a fixed size
b. You cannot have an array of arrays
d. Clusters can contain more than one data type
A cluster can contain boolean, string and numeric.
The intensity based infra-red remote control for a retro TV doesn’t work on a sunny day, what is the best solution?
a. Increase the strength of the IR emitter
b. Use a physical wire
c. Use a modulator and demodulator
d. Train your dog
c. Use a modulator and demodulator
An electrical isolation circuit is important because it can:
a. Stop electrocution
b. Reduces problems due to improper grounding
c. Protects sensitive measurement equipment
d. Reduces the effects of high frequency noise
a. Stop electrocution
b. Reduces problems due to improper grounding
c. Protects sensitive measurement equipment
Which of the following are factors in choosing sensors?
a. Power consumption
b. Lifetime
c. Economic factors
d. Linearity
a. Power consumption
b. Lifetime
c. Economic factors
d. Linearity
A sensor has an output range of 0-5V. The DAQ system is 4-bit with an input range of 0-10V. State 2 amendments to improve the DAQ system performance?
a. Use an isolation circuit
b. Amplify the sensor output with a gain of 2
c. Use a modulator circuit
d. Use a higher bit system to improve the resolution
b. Amplify the sensor output with a gain of 2
d. Use a higher bit system to improve the resolution
A 4-bit DAQ system has an input range of 0-10V. Calculate the code width (resolution) of the system?
a. 1.25V
b. 2.5V
c. 0.625V
d. 0.25V
c. 0.625V
10V / 2^4 =0.625V
What does the following Block Diagram Symbol indicate?
(N with red cross/dot in bottom right)
a. The VI is set to run for a specified number of times
b. A Probe has been placed on a For Loop within the VI
c. The VI contains a For Loop which has the optional Condition Stop terminal enabled
d. A conditional probe has been placed on the VI to stop when a specific numeric value is detected
c. The VI contains a For Loop which has the optional Condition Stop terminal enabled.
So e.g. can be used to stop the loop on an error
Illustrate the 3 types of error on the chart?
Total Error = Bias Error + Random Error
Bias Error = True Value vs True Average
Random Error = True Average vs Measured Value
Static nonlinearity is dependent on what 4 factors?
Temperature
Vibration
Acoustic noise level
Humidity
What is Direct Memory Access?
When data is transferred between the DAQ and computer memory directly. I.e. circumventing the CPU.
What is Interrupt Request?
IRQ transfers rely on the CPU. So more computationally heavy.
What is meant by determinism?
A deterministic system is a system where no randomness is involved in the development of future states of the system.
When would you use buffered I/O?
- Many samples that are acquired at a rate faster than is practical to display, store or analyse.
- Data is acquired/displayed continuously on the fly.
- The sampling period must be precise.
- If the LabVIEW vi specifies it uses buffered, not nonbuffered,
When would you use nonbuffered I/O?
- The data set is small and short.
- To reduce memory overhead, as buffered takes up extra memory.
- If the LabVIEW vi specifies it uses nonbuffered, not buffered,
Is this array initialised or uninitialised?
It is uninitialised as has no default values.
What is the difference between these two wires going into the loop?
The top one does not auto-index.
The bottom one does auto-index. I.e. iteration 1 = column
The following shows a state machine. What do the two boxes represent?
Left is the state functionality code.
Right is the transition code.
What is the role of a transducer?
To convert energy from one type such as temperature, strain pressure or light into another.
Essentially, physical quantities to electrical quantities such as voltage or resistance.
What would be an example of when we would we use an amplifier close to the signal source to improve SNR?
Playing a guitar through a sound system. Low voltage signal out could pick up noise when in the cables, so we pre-amplify it before sending it out.
What are the advantages of foil strain and fibre optic gauges? (multiple answers are correct)
a. Compact
b. Immune to EM
c. Cheapest
d. Very high resolution
Foil strain is the cheapest and most common.
Fibre optic is the compact but most expensive.
Piezoelectric strain sensor is the very high resolution.
Describe modulated infrared and why it’s useful?
IR light source is flashed at a specific frequency. The detector also runs at the same frequency (matches it). The benefit of this is that flashes and hence information can be detected despite external interference such as ambient light and reflections. This is used in IR remotes and proximity sensors.
How do the loops stop in this example?
The loops do not stop since the loop control is outside the while loops. Press run, false loop control is inputted into the loops. The loops continue to run. Loop control is pressed and now true is waiting to go into the loop. But it can only enter the loop once the loop stops.
How do the loops stop in this example?
With the loop control inside the while loop. Loop 1 will stop when = true. This true value will then be sent out of loop 1 to loop 2. Loop 2 will run once, and then stop.
What is an FPGA? And what does it help to do?
It is an integrated circuit that can be programmed to deterministically perform a task.
They can help to achieve superior performance.
What is a coercion dot?
A red dot that is highlighted by labVIEW if you use data that is different but labVIEW can convert it for you as similar. E.g. orange and blue added together
What are the various classifications for filters?
Linear / Non-linear Time-invariant / Time-variant Analog / Digital Discrete / Continuous time Passive / Active
What type of filter is this? And how much attenuation is provided by the filter?
This is a low pass filter.
25 dB to -15 dB. Hence, 25 + 15 = 40dB
What type of filter is this? And what attenuation is needed to ensure the signal level is 20dB above the interference?
This is a high pass filter. 1kHz signal with 60Hz noise at 40dB. We can apply a 60dB signal at 60Hz to ensure the signal level is 20dB above the interference
Describe the desirable and undesirable filter characteristics.
Desired:
- A flat response (desired signal isn’t altered).
- Sharp transition (to prevent interference).
Undesired:
- Passband ripple where the frequencies we want are distorted.
- Slow transition.
- Stopband ripple where the frequencies we don’t want are distorted and hence can appear.
What type of filter is this?
This is bandpass filter.
What are Butterworth filters designed to do? And what are their characteristics?
They are a common filter designed to have as flat a frequency as possible in the pass band. I.e. the most accurate desired signal.
Characteristics:
Smooth response at all frequencies.
A perfect pass band and stop bands. So pass band completely flat, and stop band pinned to 0.
Butterworth are often classed by their order. Think higher order polynomial = more responsive. So rapid cut off.
