Job Description

ON.energy is building the power infrastructure that makes the AI era possible. As AI demand surges past what the grid and traditional data centers can support, ON.energy provides a new class of power technology proven at gigawatt scale and trusted by the world’s leading cloud and AI companies. Our systems are already deployed across 2.5 GW of hyper-scale campuses, validated by top U.S. national labs, and certified for grid-safe operation by major utilities. With real products in the field, we’re scaling faster than the grid can, transforming power from a bottleneck into a competitive advantage for the companies building the future.

The Quality Assurance Engineer is responsible for hands-on experience in PLC programming, industrial protocol testing, and Python-based test automation. Skilled in designing and executing functional and integration test cases across PLC platforms and communication protocols.

Key Responsibilities:

Design, develop, and execute Unit tests, functional, integration, and regression test cases for PLC-based control systems
Write and maintain Python-based automated test scripts for testing PLC I/O, HMI interfaces, and communication protocols
Develop, review, and validate PLC code (Ladder Logic, Function Block Diagram, Structured Text) across Siemens S7-1200/1500
Collaborate with controls engineers to define acceptance criteria and validate system requirements
Identify, document, and track defects using tools such as Azure Devops or equivalent; lead root cause analysis for critical failures
Conduct Hardware-in-the-Loop (HIL) and Software-in-the-Loop (SIL) testing where applicable
Produce clear test plans, reports, and traceability matrices aligned with release timelines

Required Experience & Skills

University degree in Software Engineering, Computer Science, Quality Engineering, or a related technical field.
5+ years of hands-on experience in PLC programming and testing across Siemens platform.
5+ years of experience building and maintaining automated test frameworks using pytest or equivalent python framework.
3–5 years of experience with Siemens TIA Portal for PLC development, diagnostics, and commissioning support.
Experience designing and executing functional and integration tests, including test case development, defect tracking, and validation of fixes.
Working knowledge of industrial communication protocols such as S7, Modbus TCP/RTU, and OPC-UA.

Preferred Experience

Proficiency in automated unit testing the PLC Logic
Experience with SCADA systems
Familiarity with Agile / Scrum methodologies in industrial settings
Knowledge of functional safety standards such as IEC 61508 / IEC 62061

For US-based roles - What you’ll get:

Competitive salary + annual performance-based bonus eligibility
Medical, dental, and vision insurance
401(k) with company match
Paid time off and company holidays

For Mexico-based roles - What you’ll get:

Competitive salary + annual performance bonus eligibility
Christmas Bonus (Aguinaldo): 30 days
Major medical expenses and life insurance
Paid time off and holidays (per local policy)

For all roles:

Professional development and growth opportunities
Opportunity to grow with a mission-driven team shaping the future of clean energy
Equal Opportunity: ON.energy is committed to equal employment opportunity and to maintaining a work environment free of harassment, discrimination, or retaliation.
Accommodations: If you need an accommodation during the application process, email recruitment@onenergystorage.com
Benefits vary by role and location and are subject to change.

PLC Automation Engineer - OnEnergy

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