1. What is the primary purpose of calibrating a field instrument?

• a) To repair any physical damage to the instrument.
• b) To compare the instrument's readings to a known standard and make adjustments if necessary.
• c) To clean the internal components of the instrument.
• d) To determine the instrument's maximum operational lifespan.

2. The documented readings of an instrument before any adjustments are made during calibration are known as:

• a) As Left data
• b) Final data
• c) As Found data
• d) Initial settings

3. In a 5-point calibration, what are the typical calibration points checked?

• a) 0%, 25%, 50%, 75%, 100%
• b) 0%, 20%, 40%, 60%, 80%, 100%
• c) 10%, 30%, 50%, 70%, 90%
• d) 0%, 50%, 100%

4. The difference between the highest and lowest value that an instrument can measure is called its:

• a) Range
• b) Span
• c) Setpoint
• d) Bias

5. A pressure transmitter has a calibrated range of 0 to 200 psi. What is its span?

• a) 100 psi
• b) 200 psi
• c) 0 psi
• d) 400 psi

6. Hysteresis error in an instrument is the difference in output reading for the same input when:

• a) Approached from a lower value versus a higher value.
• b) Measured at different ambient temperatures.
• c) Measured by two different technicians.
• d) The instrument is powered on and off.

7. Which of the following is the first adjustment typically made during the calibration of a standard analog transmitter?

• a) Span adjustment
• b) Linearity adjustment
• c) Zero adjustment
• d) Damping adjustment

8. A "smart" transmitter with HART protocol offers which of the following advantages during calibration?

• a) It never requires calibration.
• b) It can be calibrated remotely.
• c) It is immune to all forms of interference.
• d) It only measures temperature.

9. The gradual change in an instrument's measurement over time is known as:

• a) Drift
• b) Error
• c) Uncertainty
• d) Fluctuation

10. What does the term "traceability" in calibration refer to?

• a) The ability to track the location of an instrument in the field.
• b) The unbroken chain of comparisons to a national or international standard.
• c) The ease with which an instrument can be calibrated.
• d) The type of cable used to connect the instrument.

11. For a standard 4-20 mA current loop, a reading of 12 mA corresponds to what percentage of the measured value?

• a) 25%
• b) 50%
• c) 75%
• d) 100%

12. When calibrating a differential pressure (DP) level transmitter on a closed tank, what is typically done to the low-pressure side?

• a) It is vented to the atmosphere.
• b) It is connected to the top of the tank to compensate for vapor pressure.
• c) It is filled with the process liquid.
• d) It is sealed and left empty.

13. Which of the following is a common tool used for calibrating pressure gauges in the field?

• a) A multimeter
• b) A deadweight tester
• c) A signal generator
• d) An oscilloscope

14. The "As Left" data in a calibration certificate represents:

• a) The readings of the instrument as it was found before calibration.
• b) The readings of the instrument after calibration and adjustments.
• c) The acceptable tolerance for the instrument.
• d) The date the instrument was last calibrated.

15. A linearity error in an instrument means that:

• a) The output is not a straight-line relationship with the input.
• b) The instrument cannot measure at its lower range.
• c) The instrument's zero point is incorrect.
• d) The instrument's span is incorrect.

16. The acceptable deviation of a measurement from the true value is known as:

• a) Tolerance
• b) Error
• c) Range
• d) Uncertainty

17. For calibrating a thermocouple, the most accurate reference would be:

• a) A mercury thermometer
• b) A precision RTD (Resistance Temperature Detector)
• c) A dry block calibrator with a certified probe
• d) An infrared pyrometer

18. What is the purpose of a 3-way manifold on a differential pressure transmitter?

• a) To allow for three different types of inputs.
• b) To isolate, equalize, and vent the pressure for safe removal and calibration.
• c) To amplify the input signal.
• d) To convert the pressure reading to a temperature reading.

19. If a pressure transmitter with a range of 0-150 bar and a 4-20 mA output is reading 8 mA, what is the corresponding pressure?

• a) 25 bar
• b) 37.5 bar
• c) 50 bar
• d) 75 bar

20. Zero suppression in a transmitter is used when:

• a) The measured variable is always zero.
• b) The zero point of the measurement range is below atmospheric pressure.
• c) The zero point of the measurement range is above the transmitter's lower range limit.
• d) The transmitter has a negative span.

21. In a field calibration, what is the primary reason for checking the loop power supply?

• a) To ensure the transmitter has enough power to operate correctly.
• b) To measure the resistance of the loop.
• c) To verify the color code of the wiring.
• d) To adjust the brightness of the instrument's display.

22. Which part of a pH probe requires regular calibration?

• a) The cable
• b) The glass electrode
• c) The mounting threads
• d) The temperature sensor

23. A "turndown ratio" for a transmitter refers to:

• a) The ratio of its maximum span to its minimum span.
• b) The number of times it can be turned on and off.
• c) The ratio of its input signal to its output signal.
• d) The time it takes for the reading to stabilize.

24. Which of the following is a non-contact method for level measurement calibration?

• a) Using a dipstick
• b) Using a sight glass
• c) Using an ultrasonic level transmitter and a measuring tape
• d) Using a differential pressure transmitter

25. Before performing a calibration on a device in a live process, what is the most critical first step?

• a) Order a new instrument.
• b) Inform the control room operator and follow proper lockout/tagout procedures.
• c) Clean the exterior of the instrument.
• d) Check the weather forecast.

26. The span adjustment on a transmitter primarily corrects for:

• a) Zero errors
• b) Gain or slope errors
• c) Linearity errors
• d) Hysteresis errors

27. A flow meter is being calibrated. What would be a suitable standard for comparison?

• a) A calibrated bucket and stopwatch
• b) A master flow meter with known accuracy
• c) A pressure gauge
• d) A temperature sensor

28. An "Out of Tolerance" (OOT) condition found during calibration implies that:

• a) The instrument was functioning perfectly.
• b) The instrument's readings were outside the acceptable limits.
• c) The calibration was performed incorrectly.
• d) The wrong standard was used.

29. What information is typically found on a calibration sticker?

• a) The purchase price of the instrument.
• b) The date of calibration, the due date for the next calibration, and the technician's initials.
• c) The detailed "As Found" and "As Left" data.
• d) The complete operational manual of the instrument.

30. The process of adjusting a controller to optimize its performance in response to process changes is known as:

• a) Calibration
• b) Commissioning
• c) Tuning
• d) Verification