Instrumentation Engineer interview questions & mock practice

Common Instrumentation Engineer interview questions include: How do you measure flow, and what is the difference between an orifice and a venturi? What is the difference between a thermocouple and an RTD? Explain a 4-20 mA signal and why it is preferred over 0-10 V. What is the difference between a PLC and a DCS? Interviews usually run across 4 rounds — Technical screening, Control systems round, Field & calibration round, HR & fit. Practise them with the free timed practice on this page.

A typical Instrumentation Engineer interview has 4 rounds: Technical screening (Measurement of pressure, temperature, flow and level, and transmitter basics.); Control systems round (PLC, DCS, SCADA, control loops and PID tuning.); Field & calibration round (Calibration, loop checking, P&ID reading and hazardous-area concepts.); HR & fit (Commissioning experience, safety systems and cross-discipline coordination.).

To prepare for an Instrumentation Engineer interview: Master the four core measurements — pressure, temperature, flow and level — with the instruments and principles for each. Understand control systems end to end: PLC, DCS, SCADA, the control loop and PID tuning basics. Practise reading P&IDs and decoding instrument tag numbers per ISA standards. Then rehearse every question out loud with the timed practice on this page before the real thing.

Core Instrumentation Engineer skills tested in interviews include Process Instrumentation, PLC & DCS, SCADA, PID Control, Calibration, P&ID Reading, SIS / SIL. OnJob shows you exactly which of these skills stand between you and a 100% match on every live Instrumentation Engineer job.

Yes. The questions, the answer guidance and the timed practice on this page are free and need no signup. With a free OnJob account you can also take timed role tests and free certification tests. Personalised AI role and skill tests are part of the paid plans.