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Certificate of Qualification Instrumentation and Control
Technician (447A) ACTUAL EXAM QUESTIONS AND CORRECT
VERIFIED SOLUTIONS LATEST UPDATE THIS YEAR – JUST
RELEASED
EXAM COVERAGE FOR 447A (Instrumentation and Control Technician)
Principles of 4-20 mA loop calculations, voltage, current, and resistance (Ohm’s Law). Pressure
measurement including transmitters, differential pressure (DP), deadweight testers, gauges,
switches, three-valve manifolds, and impulse lines. Temperature measurement using RTDs (2,
3, 4-wire), thermocouples (types J, K), thermowells, cold junction compensation, and millivolt
signals. Level measurement technologies: displacers, capacitance probes, radar, guided wave
radar, rotameters, and hydrostatic DP. Flow measurement: orifice plates, vortex shedding,
turbine meters, magnetic flowmeters, and rotameters. Pneumatic controls: I/P transducers, 3-
15 psi signals, proportional band, gain, controllers (PID), flapper/nozzle, relays, and valve
positioners. Control valves: air-to-open/close, fail-safe actions, characteristics (linear, equal
percentage, quick opening), seat leakage, and actuators. Electrical fundamentals: AC/DC
circuits, solenoids, relays, fuses, power supplies, motor inrush, and multimeter usage. Loop
checking, HART communicators, calibration procedures, error calculation (zero, span,
hysteresis), troubleshooting open/short circuits, and loop-powered devices. Process
dynamics: dead time, time constant, gain margin, oscillation, offset, and PID tuning (integral,
derivative). Safety and installation practices: thermowell sizing, grounding, stilling wells,
snubbers, chemical seals, and impulse line tracing.
1. A technician installs a 4-20 mA transmitter with a 250 Ω resistor to convert to a 1-5 VDC signal
for a PLC input. If the loop current is 12 mA, what voltage is measured across the resistor?
A) 1 V
B) 2 V
C) 3 V
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D) 4 V
Answer: C
RATIONALE: V = I × R = 0.012 A × 250 Ω = 3.0 V.
2. A differential pressure transmitter is used to measure liquid level in an open tank. The low-
pressure side is vented to atmosphere. If the tank level rises, the differential pressure:
A) Decreases
B) Increases
C) Remains constant
D) Fluctuates randomly
Answer: B
RATIONALE: Higher liquid level increases hydrostatic pressure at the high-pressure tap, so DP
increases.
3. A control valve fails closed on loss of pneumatic signal. Which action does this describe?
A) Air-to-open
B) Air-to-close
C) Fail-last
D) Fail-locked
Answer: A
RATIONALE: Air-to-open means loss of air pressure causes spring to close the valve.
4. A technician calibrates a pressure gauge using a deadweight tester. The gauge reads 102 psi
when 100 psi is applied. The error as a percentage of span (0-200 psi) is:
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A) 1%
B) 2%
C) 5%
D) 10%
Answer: A
RATIONALE: Error = 2 psi; span = 200 psi; (2/200)×100 = 1%.
5. A RTD has a resistance of 100 Ω at 0°C and 138.5 Ω at 100°C. What is the approximate
temperature when resistance is 119 Ω?
A) 25°C
B) 50°C
C) 75°C
D) 100°C
Answer: B
RATIONALE: Change 38.5 Ω per 100°C = 0.385 Ω/°C; (119-100)=19 Ω; 19/0.385 ≈ 49.4°C.
6. A 4-20 mA loop powers a transmitter and a display. Total loop resistance is 500 Ω. What
minimum supply voltage is needed?
A) 10 V
B) 12 V
C) 15 V
D) 24 V
Answer: A
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RATIONALE: V = I×R = 0.020 A × 500 Ω = 10 V (plus transmitter burden, but minimum
theoretical).
7. A pH probe is stored dry for a week. When reinstalled, it reads slowly and erratically. Most
likely cause:
A) Cables too long
B) Dehydrated glass bulb
C) Temperature error
D) Ground loop
Answer: B
RATIONALE: pH glass bulbs must remain hydrated; drying damages the gel layer.
8. A pneumatic PID controller has proportional band = 50%. If the error changes by 10%, the
output change is:
A) 5%
B) 10%
C) 20%
D) 50%
Answer: C
RATIONALE: Gain = 100%/PB = 2; output change = gain × error = 2×10% = 20%.
9. A technician measures 250 VAC between neutral and ground at a panel. This indicates:
A) Normal condition
B) Open neutral
Certificate of Qualification Instrumentation and Control
Technician (447A) ACTUAL EXAM QUESTIONS AND CORRECT
VERIFIED SOLUTIONS LATEST UPDATE THIS YEAR – JUST
RELEASED
EXAM COVERAGE FOR 447A (Instrumentation and Control Technician)
Principles of 4-20 mA loop calculations, voltage, current, and resistance (Ohm’s Law). Pressure
measurement including transmitters, differential pressure (DP), deadweight testers, gauges,
switches, three-valve manifolds, and impulse lines. Temperature measurement using RTDs (2,
3, 4-wire), thermocouples (types J, K), thermowells, cold junction compensation, and millivolt
signals. Level measurement technologies: displacers, capacitance probes, radar, guided wave
radar, rotameters, and hydrostatic DP. Flow measurement: orifice plates, vortex shedding,
turbine meters, magnetic flowmeters, and rotameters. Pneumatic controls: I/P transducers, 3-
15 psi signals, proportional band, gain, controllers (PID), flapper/nozzle, relays, and valve
positioners. Control valves: air-to-open/close, fail-safe actions, characteristics (linear, equal
percentage, quick opening), seat leakage, and actuators. Electrical fundamentals: AC/DC
circuits, solenoids, relays, fuses, power supplies, motor inrush, and multimeter usage. Loop
checking, HART communicators, calibration procedures, error calculation (zero, span,
hysteresis), troubleshooting open/short circuits, and loop-powered devices. Process
dynamics: dead time, time constant, gain margin, oscillation, offset, and PID tuning (integral,
derivative). Safety and installation practices: thermowell sizing, grounding, stilling wells,
snubbers, chemical seals, and impulse line tracing.
1. A technician installs a 4-20 mA transmitter with a 250 Ω resistor to convert to a 1-5 VDC signal
for a PLC input. If the loop current is 12 mA, what voltage is measured across the resistor?
A) 1 V
B) 2 V
C) 3 V
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D) 4 V
Answer: C
RATIONALE: V = I × R = 0.012 A × 250 Ω = 3.0 V.
2. A differential pressure transmitter is used to measure liquid level in an open tank. The low-
pressure side is vented to atmosphere. If the tank level rises, the differential pressure:
A) Decreases
B) Increases
C) Remains constant
D) Fluctuates randomly
Answer: B
RATIONALE: Higher liquid level increases hydrostatic pressure at the high-pressure tap, so DP
increases.
3. A control valve fails closed on loss of pneumatic signal. Which action does this describe?
A) Air-to-open
B) Air-to-close
C) Fail-last
D) Fail-locked
Answer: A
RATIONALE: Air-to-open means loss of air pressure causes spring to close the valve.
4. A technician calibrates a pressure gauge using a deadweight tester. The gauge reads 102 psi
when 100 psi is applied. The error as a percentage of span (0-200 psi) is:
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A) 1%
B) 2%
C) 5%
D) 10%
Answer: A
RATIONALE: Error = 2 psi; span = 200 psi; (2/200)×100 = 1%.
5. A RTD has a resistance of 100 Ω at 0°C and 138.5 Ω at 100°C. What is the approximate
temperature when resistance is 119 Ω?
A) 25°C
B) 50°C
C) 75°C
D) 100°C
Answer: B
RATIONALE: Change 38.5 Ω per 100°C = 0.385 Ω/°C; (119-100)=19 Ω; 19/0.385 ≈ 49.4°C.
6. A 4-20 mA loop powers a transmitter and a display. Total loop resistance is 500 Ω. What
minimum supply voltage is needed?
A) 10 V
B) 12 V
C) 15 V
D) 24 V
Answer: A
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RATIONALE: V = I×R = 0.020 A × 500 Ω = 10 V (plus transmitter burden, but minimum
theoretical).
7. A pH probe is stored dry for a week. When reinstalled, it reads slowly and erratically. Most
likely cause:
A) Cables too long
B) Dehydrated glass bulb
C) Temperature error
D) Ground loop
Answer: B
RATIONALE: pH glass bulbs must remain hydrated; drying damages the gel layer.
8. A pneumatic PID controller has proportional band = 50%. If the error changes by 10%, the
output change is:
A) 5%
B) 10%
C) 20%
D) 50%
Answer: C
RATIONALE: Gain = 100%/PB = 2; output change = gain × error = 2×10% = 20%.
9. A technician measures 250 VAC between neutral and ground at a panel. This indicates:
A) Normal condition
B) Open neutral
