Staff / Principal PLC Controls Engineer

Job Description

Job Description

Staff / Principal PLC Controls Engineer – Test & Integration About the Role

We are seeking a Staff/Principal-level PLC Controls Engineer to take ownership of PLC programming, controls integration, and commissioning for advanced test systems supporting a high-volume manufacturing environment.

Why This Role Is Open

The company is scaling production toward a 225-unit build rate while simultaneously upgrading its test-stand infrastructure and controls architecture .

The existing PLC system is functional, but a significant amount of control logic currently resides directly in the PLC. The engineering team is transitioning portions of that functionality into product controllers and needs to establish reliable communication between the PLC and those controllers.

This is not a ground-up controls development project . The existing PLC code and functionality are already in place. The immediate need is for an experienced controls engineer who can step into the existing CODESYS/Structured Text codebase, understand how it works, determine what logic needs to be removed or modified, and implement the required PLC-to-controller communication with minimal direction.

At the same time, the team is updating its test stands. This engineer will help verify the updated systems before production units arrive, including instrumentation, sensors, PLC I/O, signal scaling, wiring, pinouts, and control-panel functionality.

The team is targeting a 225-unit build rate , so they need a true controls SME who can hit the ground running and help move the upgraded test infrastructure into production readiness.

What You'll Do

• Develop, modify, debug, and maintain PLC programs using CODESYS and Structured Text (ST) .

• Review and understand existing PLC code and control architecture with minimal direction.

• Identify existing PLC logic that needs to be removed, modified, or transitioned to product controllers.

• Develop PLC-to-product-controller communication and associated control logic.

• Integrate product controllers into existing and newly updated test stands.

• Modify proven PLC functionality while preserving existing system performance and reliability.

• Troubleshoot PLC logic, I/O, instrumentation, sensors, wiring, pinouts, and control-panel issues.

• Verify that instrumentation is properly connected to the PLC and that signals are reading, scaling, and outputting correctly.

• Support electrical troubleshooting during system integration and commissioning.

• Commission updated test stands and verify system functionality before production units arrive.

• Work across controls, electrical, mechanical, systems, and manufacturing teams to resolve integration issues.

• Serve as the controls SME during system integration, commissioning, and production readiness.

• Identify technical issues quickly, determine root cause, and implement solutions independently.

• Support improvements to controls architecture, test-system reliability, and production readiness.

• Document PLC changes, system updates, troubleshooting activities, and commissioning results.

Technical Environment

• CODESYS

• Structured Text (ST)

• PLC programming and controls architecture

• PLC-to-product-controller communication

• Product controllers

• Industrial I/O

• Sensors and instrumentation

• Control panels and electrical systems

• Automated test stands

• System integration and commissioning

• High-volume manufacturing equipment

Required Qualifications

• Staff, Principal, or equivalent senior-level PLC/Controls engineering experience .

• Strong hands-on experience developing and modifying PLC programs.

• Expert-level experience with Structured Text .

• Professional experience with CODESYS or a comparable IEC 61131-3 PLC programming environment, with the ability to work directly in CODESYS.

• Demonstrated ability to enter an existing PLC codebase, understand the logic, and make changes independently.

• Experience developing communication between PLCs and external/product controllers.

• Strong understanding of PLC architecture, I/O, instrumentation, sensors, and control systems.

• Strong electrical troubleshooting skills, including wiring, pinouts, control panels, sensors, and PLC I/O.

• Experience with system integration, commissioning, or automated test equipment.

• Ability to troubleshoot problems across both PLC software and physical electrical hardware.

• Ability to work independently and make technical decisions with minimal supervision.

• Strong communication and cross-functional collaboration skills.

Preferred Qualifications

• Experience with Rockwell/Allen-Bradley, Siemens, or other industrial PLC platforms.

• Experience with industrial communication protocols.

• Experience integrating embedded/product controllers with PLC-based systems.

• Experience modifying existing PLC architecture rather than developing systems exclusively from scratch.

• Experience with automated test stands, laboratory equipment, or production test systems.

• Experience supporting high-volume manufacturing environments.

• Ability to read and interpret electrical schematics.

• Experience with instrumentation scaling, signal validation, and I/O commissioning.

What We're Looking For

This role requires more than someone who can troubleshoot a PLC. We need a controls SME who can write code, understand an existing architecture, determine what needs to change, implement the changes, and validate the physical system .

The right engineer should be comfortable taking ownership of an existing PLC program and quickly determining:

• What logic needs to remain.

• What logic needs to be removed.

• What functionality needs to move to the product controller.

• How the PLC should communicate with the product controller.

• Whether sensors and instrumentation are connected and scaled correctly.

• Whether wiring, pinouts, I/O, and control-panel connections are functioning correctly.

• How to diagnose and resolve issues without extensive hand-holding.

Recruiter Screening Questions PLC / CODESYS / Programming

1. How much hands-on experience do you have programming PLCs using CODESYS?

2. How strong are you with Structured Text? What percentage of your PLC programming experience has been in Structured Text?

3. Have you inherited an existing PLC codebase and had to understand and modify it with minimal direction? Walk me through an example.

4. Have you removed existing PLC logic and moved that functionality into a separate controller or embedded product controller?

5. Have you developed communication between a PLC and an external controller? What PLCs, controllers, and communication protocols did you use?

6. If given an existing PLC program that is functioning but contains control logic that needs to be removed and replaced with product-controller functionality, how would you approach that change?

Integration / Commissioning

1. Have you worked on automated test stands or test equipment? What were you responsible for?

2. Tell me about a commissioning project where you had to verify that sensors or instrumentation were communicating correctly with the PLC.

3. How comfortable are you troubleshooting a sensor that is reading incorrectly, improperly scaled, or not communicating?

4. Can you troubleshoot wiring, pinouts, PLC I/O, and control-panel issues? Give me an example.

5. Have you worked directly with both PLC code and the physical electrical system? Tell me about a problem where you had to troubleshoot both sides.

Senior-Level Ownership

1. How independently can you operate when entering an unfamiliar PLC codebase?

2. What is the most complex PLC controls system you have personally owned or modified?

3. Have you supported integration and commissioning in a manufacturing or production environment?

4. Are you comfortable operating as the controls SME for a project, making technical decisions and driving issues to resolution without extensive direction?

Ideal Candidate Profile

The strongest candidate will have:

• CODESYS

• Structured Text

• Advanced PLC programming

• PLC-to-controller communication

• Product controller integration

• Electrical troubleshooting

• Instrumentation and sensor integration

• PLC I/O

• Control-panel troubleshooting

• Automated test-stand experience

• System integration and commissioning

• Manufacturing or production environment experience

• Staff/Principal/SME -level ownership

Success in the Role

Success means being able to hit the ground running and take ownership of the controls work without requiring extensive training or direction.

The engineer will help transition existing PLC functionality toward product-controller-based control, establish reliable PLC-to-controller communication, integrate updated test stands, and ensure instrumentation and electrical systems function correctly.

With the organization targeting a 225-unit build rate , this position has a direct impact on production readiness, test capacity, and the reliability of the manufacturing operation.

You should be proficient in:

• PLC Troubleshooting Skills
• Electrical Schematics
• Single and Three Phase Power
• 120/208/240/480 Voltage Systems
• Industrial Robot Programming
• Design for Assembly (DFA)
• PLC Programming Experience
• SCADA Experience
• Electrical / Electronic Systems
• High Voltage Systems
• Equipment Installation & Wiring
• Access Control Systems
• Aerospace Manufacturing

Machines & technologies you'll use:

• Variable Frequency Drives (VFD)
• CAD Software (Solid Edge, Siemens NX, Catia, Pro-E / Creo, NX CAD (Siemens), Solidworks, Onshape, Autodesk Inventor, AutoCAD)
• Programmable Logic Controller (PLC) (Beckoff, Allen Bradley, Fanuc, Schneider Electric, Mitsubishi, Modicon, Omron, B&R Industrial Automation, Siemens, Panasonic, Sigmatek)
• Vision System
• Servo Motors
• Industrial Robot