Controls Engineer Interview Questions UK: 8 Real Questions and What Interviewers Want

Most Controls Engineer interviews in the UK follow a pattern, and knowing it beats guessing. Below are eight questions from our bank of 16, each with a note on what the interviewer is really after.

Eight Controls Engineer interview questions, and what the interviewer is thinking

1. What does a controls engineer do day to day, and why did you choose this specialism?

Why they ask: To confirm you understand the role beyond programming, including process knowledge and site work.

2. How do you tune a PID loop, and how do you decide which terms you need?

Why they ask: PID tuning is fundamental to a controls engineer, and the answer shows depth of understanding.

3. When would you use cascade or feedforward control, and can you give an example of each?

Why they ask: Advanced control strategies show whether you can improve performance beyond basic PID.

4. How do you size and select a control valve, and what could go wrong if you get it wrong?

Why they ask: Valve selection is a classic area where controls and process knowledge combine.

5. What information do you take from a P&ID, and how do you develop a control narrative and cause and effect matrix from it?

Why they ask: Interpreting design documents is a daily task, and clear documentation is essential for safe operation.

6. Explain the safety lifecycle for a safety instrumented function under IEC 61511 and why proof testing matters.

Why they ask: Safety instrumented systems are high consequence, and they check you respect the standard.

7. Operators say a flow loop has started hunting after a new control valve was installed. How do you investigate?

Why they ask: They want logical diagnosis of a typical loop problem.

8. Tell me about a time you improved the performance of a control loop or control strategy. What was the result?

Why they ask: They want evidence that you deliver measurable process benefits.

A sample answer to question 1

What does a controls engineer do day to day, and why did you choose this specialism?

A controls engineer makes sure a process or machine does what it should, safely and consistently. In a typical day I might review a P&ID and write or update a control narrative, configure loops and alarms in the DCS or PLC, tune a loop that is not performing, or attend a commissioning session to check instruments and interlocks. I also work with process engineers, operations and instrument technicians, so communication matters as much as technical skill. I chose controls because it combines mathematics and physics with practical outcomes. Seeing a tuned loop hold a temperature steady or a well-designed sequence start a plant smoothly is very satisfying. I like that the work is varied, ranging from instrumentation and electrical design to software and process understanding, and that it directly affects safety, product quality and energy use. I am also interested in how data and advanced control can make plants more efficient, which keeps the job interesting.

Common mistake to avoid: Describing only software; Giving no reason for choosing the field

Want the rest?

Full model answers, key points and common mistakes for all 16 questions are on the Controls Engineer interview questions page. The first five are free, no sign-up needed.