CTC CTC Test Instrumentation and Measurement Systems 1 — Questions and Answers
Question 1: What is the primary purpose of a signal conditioner in a CTC test instrumentation setup?
- To amplify, filter, and convert raw sensor signals into a usable format for data acquisition systems (Correct answer)
- To store raw sensor data on removable media for post-test review
- To generate artificial test signals for system calibration checks
- To transmit data wirelessly to remote monitoring stations
Correct answer: To amplify, filter, and convert raw sensor signals into a usable format for data acquisition systems
Signal conditioners amplify, filter, and convert raw sensor outputs so the data acquisition system can accurately record and interpret the measurements.
Question 2: During a CTC test, a strain gauge reads a value outside its calibrated range. What is the correct immediate action?
- Replace the strain gauge with a spare and continue the test
- Flag the data channel as suspect and notify the Test Director before proceeding (Correct answer)
- Ignore the reading if it only briefly exceeds the calibrated range
- Recalibrate the gauge in-place without pausing the test sequence
Correct answer: Flag the data channel as suspect and notify the Test Director before proceeding
Out-of-range readings must be flagged and reported to the Test Director immediately so a GO/NO-GO decision can be made before the test continues.
Question 3: Which term describes the maximum frequency of a signal that can be accurately captured by a digital data acquisition system according to the Nyquist theorem?
- Half the sampling rate of the system (Correct answer)
- Twice the sampling rate of the system
- Equal to the sampling rate of the system
- One-quarter of the sampling rate of the system
Correct answer: Half the sampling rate of the system
The Nyquist theorem states the signal frequency must be less than half the sampling rate to avoid aliasing errors.
Question 4: A CTC must verify instrument calibration traceability. What does traceability mean in this context?
- Calibration is traceable to a recognized national standard such as NIST (Correct answer)
- All calibration records are stored in the test log binder
- The instrument has been calibrated within the last 30 days
- The sensor serial number is recorded in the test plan
Correct answer: Calibration is traceable to a recognized national standard such as NIST
Traceability means the calibration chain can be linked back to a recognized national metrology standard (e.g., NIST) through an unbroken comparison.
Question 5: What is the purpose of a shunt calibration check on a strain gauge bridge?
- To verify the sensitivity of the measurement system without physically loading the structure (Correct answer)
- To zero the bridge output before test data recording begins
- To check for electrical shorts in the bridge wiring harness
- To confirm the power supply voltage is within specification
Correct answer: To verify the sensitivity of the measurement system without physically loading the structure
A shunt calibration inserts a known resistor in parallel to simulate a predictable bridge imbalance, verifying system sensitivity without applying physical load.
Question 6: Which instrumentation specification defines the smallest detectable change in a measured value?
- Resolution (Correct answer)
- Accuracy
- Repeatability
- Hysteresis
Correct answer: Resolution
Resolution is the smallest increment of change that an instrument can detect and display in its output.
CTC CTC Test Instrumentation and Measurement Systems 1
What is the primary purpose of a signal conditioner in a CTC test instrumentation setup?