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Key Facts: SOLAS Instrumentation Exam

100

Practice Questions

OpenExamPrep

Level 6

NFQ Award (QQI Advanced Certificate Craft)

SOLAS / QQI

4 years

Minimum Apprenticeship Duration

SOLAS

4-20 mA

Analogue Signal Standard

Instrumentation standard

Phases 2, 4, 6

Off-the-Job Training Phases

SOLAS

HSA

Irish Safety Regulator

Health and Safety Authority

The SOLAS Electrical Instrumentation apprenticeship is a four-year QQI Advanced Certificate Craft at NFQ Level 6, regulated by SOLAS and delivered through Ireland's Education and Training Boards and partner colleges. Apprentices alternate off-the-job training phases (Phase 2, 4 and 6) with employer-based on-the-job phases, and are assessed by modular phase theory examinations plus practical skills tests. The syllabus covers process measurement (pressure, temperature, flow and level), control loops and PID, transmitters, sensors and calibration, final control elements and pneumatics, PLCs and electronics, and safety including hazardous areas. This free prep includes 100 research-based practice questions with explanations and an AI tutor.

Sample SOLAS Instrumentation Practice Questions

Try these sample questions to review concepts for the SOLAS Instrumentation exam. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1What is the standard analogue current signal range used to transmit a process variable in industrial instrumentation?
A.0-10 mA
B.4-20 mA
C.0-5 V DC
D.1-5 mA
Explanation: The 4-20 mA current loop is the universal analogue standard for transmitting process variables. The 4 mA 'live zero' allows a broken wire (0 mA) to be distinguished from a genuine 0% reading, while the current signal is immune to voltage drop over long cable runs.
2A 4-20 mA transmitter is measuring a temperature range of 0-200 degC. What current will it output at 100 degC?
A.8 mA
B.10 mA
C.12 mA
D.16 mA
Explanation: 100 degC is 50% of the 0-200 degC span. The output is 4 mA + (0.50 x 16 mA) = 4 + 8 = 12 mA. The span of the current signal is 16 mA (20 minus 4), so 50% of span equals the midpoint, 12 mA.
3What does the HART protocol allow that a plain 4-20 mA loop does not?
A.It increases the current range to 4-40 mA
B.It superimposes a digital signal on the 4-20 mA analogue signal for two-way communication
C.It converts the signal to a pneumatic 3-15 psi output
D.It removes the need for a power supply in the loop
Explanation: HART (Highway Addressable Remote Transducer) superimposes a low-level FSK digital signal on the standard 4-20 mA analogue current without affecting the analogue value. This allows a handheld communicator or DCS to read diagnostics, ranges, and configuration data over the same two wires.
4Which temperature sensor relies on the change in electrical resistance of a metal (typically platinum) with temperature?
A.Thermocouple
B.RTD (resistance temperature detector)
C.Thermistor with NTC characteristic only
D.Bimetallic strip
Explanation: An RTD measures temperature from the predictable change in electrical resistance of a metal element, usually platinum. The common Pt100 has a resistance of 100 ohms at 0 degC and rises in a near-linear, repeatable manner, giving high accuracy and stability.
5What is the nominal resistance of a Pt100 RTD at 0 degC?
A.10 ohms
B.100 ohms
C.120 ohms
D.1000 ohms
Explanation: A Pt100 is a platinum RTD with a nominal resistance of 100 ohms at 0 degC, which is the origin of its name. Its resistance increases by approximately 0.385 ohms per degC (the standard alpha value for industrial platinum RTDs).
6Why is a 3-wire or 4-wire connection preferred over a 2-wire connection for an RTD?
A.It increases the sensor's measuring range
B.It compensates for the resistance of the connecting lead wires
C.It allows the RTD to generate its own voltage
D.It converts the resistance signal directly to 4-20 mA
Explanation: In a 2-wire RTD the resistance of the lead wires adds directly to the measured resistance, causing an error. The 3-wire connection lets the transmitter cancel out the lead resistance, and the 4-wire (Kelvin) connection eliminates it entirely for the highest accuracy.
7On what physical principle does a thermocouple generate a measurable voltage?
A.The Seebeck effect, where a voltage arises from a temperature difference across a junction of two dissimilar metals
B.The Hall effect from a magnetic field
C.The piezoelectric effect from mechanical strain
D.The photoelectric effect from incident light
Explanation: A thermocouple uses the Seebeck effect: when two dissimilar metals are joined and the junction is at a different temperature from the reference (cold) junction, a small temperature-dependent EMF (millivolts) is produced. Measuring this EMF gives the temperature relative to the reference junction.
8What is the purpose of cold-junction compensation in a thermocouple measurement circuit?
A.To cool the measuring junction below ambient
B.To correct the reading for the temperature of the reference (cold) junction at the instrument terminals
C.To convert millivolts to a pneumatic signal
D.To electrically isolate the thermocouple from earth
Explanation: A thermocouple only measures the temperature difference between the hot (measuring) and cold (reference) junctions. Cold-junction compensation measures the terminal temperature and adds the equivalent EMF so the instrument reports the true absolute temperature of the process.
9Which thermocouple type uses Chromel-Alumel and is the most common general-purpose type?
A.Type J
B.Type K
C.Type T
D.Type R
Explanation: Type K thermocouples use a Chromel (nickel-chromium) positive leg and Alumel (nickel-aluminium) negative leg. They are the most widely used general-purpose type, covering roughly -200 to 1260 degC with good linearity and low cost.
10A pressure transmitter is calibrated for 0-10 bar. What is the measured pressure when its output is 16 mA?
A.6 bar
B.7.5 bar
C.8 bar
D.10 bar
Explanation: 16 mA represents (16-4)/16 = 12/16 = 75% of span. 75% of the 0-10 bar range is 7.5 bar. Always subtract the 4 mA live zero before calculating the percentage of span.

About the SOLAS Instrumentation Exam

The SOLAS Electrical Instrumentation apprenticeship is a four-year, NFQ Level 6 craft programme in Ireland. Apprentices alternate between off-the-job training in ETBs and colleges (Phases 2, 4 and 6) and on-the-job employer phases, and are assessed by phase theory examinations and practical tests covering process measurement, control loops, transmitters and calibration, final control elements, PLCs, electronics and safety.

Exam sponsor: SOLAS, delivered through Education and Training Boards (ETBs) and partner Educational Colleges. The requirements and fees below concern the certification or admission exam, separate from our free practice resources.

Assessment

Modular phase theory examinations across off-the-job Phases 2, 4 and 6 (Measurement, Electronics, Automatic Control, Final Control Elements and related theory), combined with practical skills assessments; this practice bank is 100 selected-response items

Time Limit

Varies by phase written examination

Passing Score

Typically 50% to pass, with higher thresholds for credit and distinction (per SOLAS/QQI phase assessment)

Exam / Certification Fees

No separate exam fee for registered apprentices

Exam sponsor website

Fees, eligibility, and exam policies can change. Confirm them with the exam sponsor before applying or paying.

Our practice resources: topics covered

We aim to reflect publicly available exam outlines and topic information in our study resources. Coverage, format, and difficulty may differ from the actual exam, and we cannot guarantee that every detail is accurate or current. Confirm exam requirements, fees, and policies with the official exam sponsor.

30%

Process Measurement (Pressure, Temperature, Flow, Level)

Pressure (gauge vs absolute, Bourdon tube), temperature (RTD/Pt100, thermocouples, cold-junction compensation), flow (orifice/DP, square-root, magnetic, Coriolis, vortex) and level (DP, radar, ultrasonic, capacitance)

20%

Control Loops & PID

Feedback control, setpoint/PV/error, PID action, proportional band and gain, loop tuning and stability, cascade control, manual/auto, ISA tagging and P&IDs

20%

Transmitters, Sensors & Calibration

4-20 mA loop and live zero, signal scaling, HART and smart transmitters, burnout, and five-point calibration with zero/span adjustment, accuracy and turndown

15%

Final Control Elements & Pneumatics

Control valves (fail action, positioners, Cv, characteristics, cavitation), actuators, solenoids, 3-15 psi signals, I/P converters and instrument air

10%

PLC, Electronics & Communications

PLC scan cycle and ladder logic, analogue/digital I/O and ADCs, diodes, transistors and op-amps, Ohm's law, and fieldbus protocols

5%

Safety & Hazardous Areas

Lock-out/tag-out, intrinsic safety and hazardous areas, emergency shutdown and SIS, relief valves, and Irish workplace safety law (HSA, 2005 Act)

Preparing for the SOLAS Instrumentation Exam

What You Need to Know

  • Passing score: Typically 50% to pass, with higher thresholds for credit and distinction (per SOLAS/QQI phase assessment)
  • Assessment: Modular phase theory examinations across off-the-job Phases 2, 4 and 6 (Measurement, Electronics, Automatic Control, Final Control Elements and related theory), combined with practical skills assessments; this practice bank is 100 selected-response items
  • Time limit: Varies by phase written examination
  • Exam / certification fees: No separate exam fee for registered apprentices Official sources

Using Our Practice Resources

  • Work through all 100 available questions
  • Review every answer and explanation
  • Track weak areas and revisit them
  • Use our AI tutor for tough concepts

SOLAS Instrumentation: Suggested Study Strategy

1Weight your study toward process measurement and control loops, which together make up the bulk of the instrumentation syllabus
2Memorise the 4-20 mA scaling rule: output mA = 4 + (percent of span x 16), and remember the 4 mA live zero
3Know the difference between an RTD (resistance change, Pt100) and a thermocouple (Seebeck EMF with cold-junction compensation), and which suits each temperature range
4For DP flow, remember flow is proportional to the square root of differential pressure, so 25% DP equals 50% flow
5Understand control valve fail action: air-to-open fails closed and air-to-close fails open, driven by the spring
6Complete all 100 practice questions and review every miss with the AI tutor before sitting each phase exam

Frequently Asked Questions

What is the SOLAS Electrical Instrumentation apprenticeship?

It is a four-year craft apprenticeship in Ireland regulated by SOLAS that leads to a QQI Advanced Certificate Craft at NFQ Level 6. Apprentices alternate off-the-job training in ETBs and colleges with on-the-job employer phases and are assessed by phase theory exams and practical tests.

What topics are covered in the instrumentation phase exams?

The phase theory examinations cover process measurement (pressure, temperature, flow and level), control loops and PID, transmitters and calibration, final control elements and pneumatics, PLCs and electronics, and safety including hazardous areas and intrinsic safety.

What passing score do the SOLAS phase exams require?

SOLAS craft phase assessments are typically graded as pass (around 50%), credit and distinction at higher thresholds. Both written theory examinations and practical skills assessments must be passed to progress through the phases.

Is there an exam fee for the instrumentation apprenticeship?

Registered apprentices do not pay a separate exam fee; phase assessments are part of the SOLAS apprenticeship. Apprentices are employed and paid, with off-the-job phases delivered through Education and Training Boards and partner colleges.

What does an instrumentation craftsperson need to know about 4-20 mA and RTDs?

The 4-20 mA current loop is the analogue signalling standard, with 4 mA as a live zero so a broken loop reads 0 mA. RTDs such as the Pt100 (100 ohms at 0 degC) measure temperature by resistance change, while thermocouples use the Seebeck effect with cold-junction compensation.

Is this free SOLAS Instrumentation practice as good as paid prep?

Our 100 practice questions cover the same syllabus areas as the SOLAS instrumentation phases, with a teaching explanation for every answer plus free daily AI tutor interactions. All content is free forever and updated for 2026.