Sensors Final - VI Concepts

Name three signal processing or signal condoning procedures

Filtering, Amplification, ADC

What is the purpose of a secondary Sensor in a DAQ

Correct for environmental conditions Correct for environmental conditions

A Pressure transducer produces an output voltage. What is the main Signal Processing step required before you can read the signal on your computer

Analog to Digital Conversion (ADC)

Is a thermistor a transducer? Why or why not?

Yes, a thermistor is a type of transducer because it converts temperature changes into a change in resistance or voltage, which can be measured.

Is a strain gage without a bridge a passive or active instrument?

A strain gage without a bridge is considered a passive instrument because it does not provide power to the system and relies on external sources for excitation.

Is a laser tachometer an analog or digital signal ? Why?

Digital: It is 0 or 1 if the beam gets reflected

A Sensor produces an output voltage in the range of 0- 0.2 V. The DAQ module used with this sensor has an ADC resolution of 16 bits and adjustable ranges of [0.1, 0.5, 2 , 5 , 10 ]. What range would you select to aquire the most accurate reading from your sensor?

0.5 to take full advantage of the ADC resolution

Which temperature sensor requires cold junction compensation?

Thermocouple, to correct for the temperature difference at the cold junction

In experiment 1, an NI-9211 was used as the DAQ module to fins the water temperature using a thermocouple. Provide two reasons why NI-9211 is more suitable for this experiment than NI-6211. (for questions like this, you will be provided with the relevant datasheet from the manufacturer. For now, refer to the technical resources documents)

The NI-9211 has a higher resolution of 24 bits, and a smaller range (80 mv)

When designing an experiment for which an objective is defined, what type of quantities (variables, parameters) one might need to identify before running the experiment.

Dependent Variables, Independent Variables, parameters, disturbances

NI-6211 has a total of 16 terminals that are termed AI (including both + and -). How many pressure transducers can be connected to this DAQ module when taking differential readings? How about for single ended measurements?

8 for differential, 16 for single-ended

What are the three "R"s that you should consider when selecting a DAQ for your application?

Resolution, Range, and Rate

The uncertainty of a sensor is reported to be 8%FS. This, however, is too large for a given application. What approach can you think of to increase confidence that your samples are likely to fall in a smaller range?

Confidence interval

Whin using a strain gage, what does the null voltage refer to?

The output voltage from the strain gage when the strain is zero

When running experiment 2, the Young’s modulus was too far off from the expected value of 200 GPa. What was the reason?

High signal-to-noise ratio

What is the highest frequency that can be observed called?

Nyquist

According to Shannon’s sampling theorem, what sampling frequency is needed to accurately reproduce the frequency of the original signal?

Twice the frequency of the original signal

Describe a concern about using the "delay" command in Arduino code for motor control ?

Losing control of the motor for as long as the code stops on the delay code line