Controls Technician
Posted Sep 30, 2026 · We last checked this listing on Oct 6, 2026
Likely interview questions for this role
Written from this job description, not a generic list. Each one notes what the interviewer is really checking.
About your past
Tell me about a time you troubleshot a PLC, servo or HMI fault that wasn't obvious. What did you check first?
What they are checking: Whether they work from the program logic and I/O status in an orderly way instead of guessing under pressure.
Tell me about a time you helped write a specification for new equipment. What did you insist on including?
What they are checking: Whether they think about maintainability and spare parts at the buying stage, not just after the machine arrives.
What would you do
You're installing a new piece of equipment and you notice the layout doesn't match the plant specification. What do you do?
What they are checking: Whether they stop and raise a spec mismatch early rather than quietly making it fit and creating a problem later.
Production wants a line back up now, but you think the fix needs another hour to be done right. How do you handle it?
What they are checking: Whether they can hold a quality and safety line while still respecting the pressure the production team is under.
About the work
Walk me through how you calibrate a pH probe and a conductivity sensor on a production line.
What they are checking: Whether they know the actual calibration steps, buffers and checks rather than just knowing the instruments exist.
A tank level transmitter is reading full but the operators swear the tank is half empty. How do you track down what's wrong?
What they are checking: How they separate a sensor fault from a wiring, scaling or process problem before they start swapping parts.
How do you go about pulling a pneumatic control valve for repair without upsetting the process or creating a safety risk?
What they are checking: Whether isolation, lockout and process coordination come before the wrench, which matters in a chemical plant.
What's your experience running conduit and pulling cable in an industrial plant? What standards do you work to?
What they are checking: Whether they have done the physical install work themselves and know the code basics that keep it safe and inspectable.
How would you explain the difference between a 4 to 20 milliamp signal and a pneumatic 3 to 15 psi signal to a newer technician?
What they are checking: Whether they understand instrument signals well enough to teach them, which shows real depth rather than memorized terms.
How do you keep track of calibration records and make sure nothing falls overdue?
What they are checking: Whether they treat documentation as part of the job, since missed calibrations can affect product quality and audits.
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Practice this out loudThe full job description
As published by Ecolab.