Senior Automation Software Engineer - PLC / CODESYS

GCS Recruitment; Kirkland (WA); Hybrid; USD 120,000 - 160,000; Full time

Job summary

GCS Recruitment seeks a Senior Automation Software Engineer with PLC/CODESYS expertise to design modular control software for high-throughput automation systems in Kirkland, WA.

The role blends software engineering with industrial controls, requiring IEC 61131-3 proficiency, EtherCAT integration, state-machine design, and hardware interfacing. Hybrid work model and agile development practices are included.

Qualifications

• 5+ years of controls/industrial automation software development required.

Responsibilities

• Design and develop control applications using CODESYS V3 or Beckhoff TwinCAT.
• Develop production-quality Structured Text programs following IEC 61131-3 standards.
• Create modular Function Blocks and reusable software libraries.
• Design machine sequencing using state machines and CASE-based logic.
• Implement fault handling, startup/shutdown, and equipment-state management.
• Apply OOP concepts such as interfaces, methods, properties, abstraction, and encapsulation.
• Integrate and troubleshoot motors, drives, sensors, actuators, MDRs, and IO-Link devices.
• Configure and troubleshoot EtherCAT communication.
• Validate software with real automation equipment.
• Review electrical schematics and control-panel documentation.
• Support commissioning and system deployment.
• Participate in design reviews, code reviews, and Agile development activities.

Skills

Controls/PLC development

CODESYS V3 or Beckhoff TwinCAT

Structured Text (IEC 61131-3)

State-machine programming

Object-oriented PLC development

EtherCAT experience

Industrial hardware integration

Git/source-control experience

Analytical/problem-solving skills

Tools

Git

Job description

Senior Automation Software Engineer - PLC / CODESYS

Location: Kirkland, WA
Work Model: Hybrid
Experience: 5+ Years

Position Summary

We are looking for a Senior Automation Software Engineer with a strong background in PLC and machine-control software development.

This engineer will build modular, reusable control applications for automated equipment and high-throughput material-handling systems. The position combines software engineering with industrial controls, making it ideal for someone who enjoys developing software while working directly with physical automation hardware.

Responsibilities

• Design and develop control applications using CODESYS V3 or Beckhoff TwinCAT.
• Develop production-quality Structured Text programs following IEC 61131-3 standards.
• Create modular Function Blocks and reusable software libraries.
• Design machine sequencing using state machines and CASE-based logic.
• Implement fault handling, recovery, startup/shutdown, and equipment-state management.
• Apply OOP concepts such as interfaces, methods, properties, abstraction, and encapsulation.
• Integrate and troubleshoot motors, drives, sensors, actuators, MDRs, and IO-Link devices.
• Configure and troubleshoot EtherCAT communication.
• Validate software with real automation equipment.
• Review electrical schematics and control-panel documentation.
• Support commissioning and system deployment.
• Participate in design reviews, code reviews, and Agile development activities.

Required Skills

• 5+ years of controls, PLC, or industrial automation software development.
• CODESYS V3 or Beckhoff TwinCAT experience.
• Strong Structured Text / IEC 61131-3 experience.
• State-machine programming experience.
• Object-oriented PLC development.
• EtherCAT experience.
• Industrial hardware integration and troubleshooting.
• Git/source-control experience.
• Strong analytical and problem-solving skills.

Preferred Experience

• Material handling
• Conveyor systems
• Sortation systems
• Warehouse automation
• Packaging automation
• IO-Link
• Linux Industrial PCs
• JSON configuration
• Electrical schematics
• C++ or Rust