PLC Systems Integration Architect; CODESYS​/ST

PLC Systems Integration Architect (CODESYS/ST)
A day in this role

You start by reviewing the latest test-stand updates: sensors are wired, I/O is mapped, and instrumentation is ready for validation. Before lunch, you dive into an existing CODESYS Structured Text codebase, tracing control logic to decide what stays on the PLC and what must transition to the product controller. In the afternoon, you stand up robust PLC-to-controller communications, scale signals correctly, and commission a station so it is production-ready.

Along the way, you partner with electrical, mechanical, systems, and manufacturing colleagues to resolve integration issues quickly and decisively.

We are scaling toward a 225-unit build rate while modernizing test-stand infrastructure and the controls architecture. The PLC system is functional, but too much logic lives in the PLC today. Your mission is to refactor that footprint, move targeted functionality into product controllers, and ensure bulletproof communications between the PLC and those controllers. This is not a ground-up build; you will step into working code and make it better, faster, and production-hardened.

• Develop, modify, debug, and sustain PLC applications using CODESYS and Structured Text (ST).
• Rapidly understand an existing controls architecture and codebase with minimal direction.
• Decide what logic remains on the PLC, what is removed, and what migrates to product controllers.
• Design and implement PLC-to-product-controller communications and related control logic.
• Integrate product controllers into current and upgraded automated test stands.
• Preserve proven behaviors while refactoring or removing legacy logic.
• Troubleshoot PLC logic, I/O, instrumentation, sensors, wiring, pinouts, and control-panel issues.
• Verify that instrumentation is properly connected and that signals read, scale, and output correctly.
• Provide hands-on electrical troubleshooting during integration and commissioning.
• Commission updated test stands and validate functionality ahead of production units.
• Act as the controls SME across integration, commissioning, and production readiness.
• Identify root causes quickly and implement durable fixes independently.
• Improve controls architecture, test-system reliability, and throughput.
• Document code changes, system updates, troubleshooting steps, and commissioning results.

CODESYSStructured Text (ST)
PLC programming and controls architecturePLC-to-product-controller communication

Product controllers

Industrial I/OSensors and instrumentation

Control panels and electrical systems

Automated test stands

System integration and commissioning

High-volume manufacturing equipment

• Senior-level PLC/controls engineering experience (Staff, Principal, or equivalent).
• Extensive hands-on PLC programming and modification experience.
• Expertise in Structured Text.
• Professional work in CODESYS or a comparable IEC 61131-3 environment, with the ability to contribute directly in CODESYS.
• Proven ability to enter, understand, and independently modify an existing PLC codebase.
• Experience implementing communications between PLCs and external or product controllers.
• Deep understanding of PLC architecture, I/O, instrumentation, sensors, and control systems.
• Strong electrical troubleshooting across wiring, pinouts, control panels, sensors, and PLC I/O.
• Background in system integration, commissioning, or automated test equipment.
• Fluency troubleshooting across both PLC software and physical hardware.
• Self-directed decision-maker with excellent cross-functional communication.

• Rockwell/Allen-Bradley, Siemens, or other industrial PLC platforms.
• Industrial communication protocols.
• Integrating embedded or product controllers with PLC-based systems.
• Modifying established PLC architectures (vs exclusively greenfield builds).
• Automated test stands, laboratory equipment, or production test systems.
• High-volume manufacturing support.
• Ability to read and interpret electrical schematics.
• Instrumentation scaling, signal validation, and I/O commissioning.

• CODESYS and ST depth: hands-on scope, percent of work in ST, and examples.
• Experience inheriting and improving an existing PLC codebase with minimal guidance.
• Shifting functionality from PLC to a separate or embedded controller: approach and lessons.
• Designing PLC-to-external-controller communications: platforms and protocols you used.
• Automated test-stand…