A controls engineer is the person who makes equipment do what the process needs. They write and change the logic in programmable logic controllers (PLCs), build the operator screens, connect machines to supervisory systems, and get a line running again when something stops. When the seat is empty, projects slip and the maintenance team ends up calling an outside integrator for every change.
Controls searches are also some of the easiest to get wrong. A job description that lists every platform on the market and says nothing about the work tends to attract the wrong people and scare off the right ones. This guide covers how to define the role, where candidates come from and how to interview for real skill.
Start with the environment, not the platform list
The same title means very different jobs depending on where the engineer sits. Before you write a posting, answer four questions.
Plant, integrator or OEM?
- End user (plant) controls engineers support equipment that is already running. Their days are about uptime, small improvements, troubleshooting with maintenance and managing outside integrators on larger projects.
- System integrator engineers design and commission new systems for many clients. They tend to have broad platform exposure, strong documentation habits and a lot of travel.
- OEM (machine builder) engineers program the same family of machines repeatedly, often with deep knowledge of one controller and one type of motion.
Each background can succeed in the other settings, but the transition takes time. An integrator engineer moving into a plant has to learn to live with a system for years. A plant engineer moving to an integrator has to get comfortable with fixed-scope projects and travel.
Brownfield or greenfield?
Supporting a twenty-year-old line with undocumented logic is a different skill from designing a new one. If most of the work is brownfield, say so, and test for it.
Which platforms are truly required?
Separate the controller and software the person must know on day one from those they can learn. A strong engineer who knows one major PLC family can usually pick up another, because the programming languages are standardized. IEC 61131-3, the international standard for PLC programming, defines the common languages (ladder diagram, function block diagram, structured text and sequential function chart). Requiring five named platforms usually shrinks the pool without improving the hire.
How much travel and on-call?
Integrator roles can be heavy travel. Plant roles may carry on-call duty for nights and weekends. Both are fine if they are stated plainly. Hidden travel or on-call is a common reason a new controls hire leaves early.
What to look for
Technical depth
- Logic and troubleshooting. Can they read someone else's code, find a fault from the symptoms and fix it without making the next fault harder to find?
- HMI and SCADA. Operator screens and supervisory control and data acquisition (SCADA) systems are where operators see the process. Good engineers design screens for the people who use them, not for themselves.
- Networks and data. More plants connect controllers to plant-wide and business systems. The ISA-95 standard describes how manufacturing control systems and enterprise systems are integrated, and engineers who understand that model are easier to put on data projects.
- Motion, drives and instrumentation, depending on your process.
Safety and standards
Controls engineers work on energized equipment and change how machines behave, so safety knowledge is part of the job, not a bonus.
- NFPA 70E, the Standard for Electrical Safety in the Workplace, covers electrical safe work practices.
- OSHA's lockout/tagout standard (29 CFR 1910.147) sets requirements for controlling hazardous energy during service and maintenance.
- NFPA 79 (electrical standard for industrial machinery) and UL 508A (industrial control panels) matter if the engineer designs panels or machines.
- ISA/IEC 62443, the series of standards for industrial automation and control system security, matters more every year as plants connect more equipment.
Ask how they apply these on a real job, not whether they have heard of them.
Credentials
Credentials are useful signals but rarely required. NCEES offers a Professional Engineer (PE) exam in Control Systems, and a PE license matters if the engineer will seal drawings or work on regulated infrastructure. The International Society of Automation (ISA) offers the Certified Automation Professional (CAP) and Certified Control Systems Technician (CCST) programs. Many strong controls engineers hold none of these and learned on the plant floor.
Where candidates come from
There is no separate federal job category for controls engineers. The Bureau of Labor Statistics' Standard Occupational Classification groups much of this work under electrical engineers (SOC 17-2071) and other engineering codes, which is one reason salary data for the title is hard to pin down. Use a named, dated source for any pay range you rely on, and compare it with what your own recent offers looked like.
Common paths into the role:
- Electrical, mechanical or computer engineering graduates who started at an integrator
- Electricians and instrumentation technicians who moved into programming
- Engineers from OEMs who want to stay in one place
- Military technicians with electronics or systems backgrounds
Many of the best candidates are not looking. They are busy keeping a plant running or commissioning a project in another state, which is why controls roles are often filled through direct outreach rather than job boards.
Interview prompts that reveal real skill
1. "Walk me through the last fault you found that took more than a day." Listen for method: what they checked first, what they ruled out, how they confirmed the fix. 2. "Here is a section of logic. What does it do, and what would you change?" Use a sanitized printout from your own system if you can. Watch how they read it, not only whether they get it right. 3. "How do you make a change on a running line?" Good answers cover backups, testing, communication with operations and lockout procedures. 4. "Tell me about a project where you handed a system off to someone else." Documentation and training separate engineers who can be supported from those who become the only person who can touch the code. 5. "What would you want to know about our plant in your first two weeks?" Strong candidates ask about the process, the people and the oldest equipment, not only the software.
A short practical exercise on a simulator or a test rig can be fair and useful. Keep it short, pay for it if it takes more than an hour, and tell candidates in advance what to expect.
Direct hire, contract or contract-to-hire?
A one-time project, such as a line installation or a migration from an old controller, may suit a contract engineer. A long-term seat that owns the plant's systems is usually a direct hire. If you are unsure whether you need a dedicated engineer or an integrator relationship, contract-to-hire lets both sides find out. We explain the permanent path in how a direct-hire search works, and if the controls hire will report to plant leadership, see how to hire a plant manager.
Work with Recruit 619
Recruit 619 recruits controls and automation engineers for plants, OEMs and integrators, from Carmel, Indiana and nationwide. If you are hiring, tell us about the role. If you are a controls engineer open to a conversation, see current openings.