QA Enginer, PLC Automation

ASCENDING; Houston (TX); On-site; USD 110,000 - 150,000; Full time

Job summary

ASCENDING seeks a Quality Assurance Engineer for PLC automation to push the envelope in energy infrastructure testing. You will lead PLC-based testing across Siemens platforms, develop Python-driven automation, and ensure robust validation of control systems and communication protocols.

Ideal candidates bring 5+ years of PLC testing experience, strong Python automation skills, and hands-on experience with Siemens TIA Portal.

Qualifications

• Degree in Software Engineering, Computer Science, Quality Engineering, or a related technical field.
• 5+ years PLC programming and testing across Siemens platform.
• 5+ years building automated test frameworks with Python (pytest or equivalent).
• 3–5 years experience with Siemens TIA Portal for PLC development and commissioning.
• Experience designing functional and integration tests, defect tracking, and validating fixes.
• Working knowledge of industrial protocols such as S7, Modbus TCP/RTU, and OPC-UA.

Responsibilities

• Design, develop, and execute unit, functional, integration, and regression tests for PLC-based control systems.
• Write and maintain Python-based automated test scripts for PLC I/O, HMI interfaces, and protocols.
• Develop, review, and validate PLC code (Ladder Logic, FBD, Structured Text) on Siemens S7-1200/1500.
• Collaborate with controls engineers to define acceptance criteria and validate requirements.
• Identify, document, and track defects using Azure DevOps or equivalent; lead root cause analysis.
• Conduct HIL/SIL testing where applicable and produce traceability matrices aligned with releases.
• Produce clear test plans and test reports to support software releases.

Skills

PLC programming

Python test automation

Test automation frameworks

Siemens TIA Portal

Industrial protocols

Education

Bachelor's degree in Software Engineering or related field

Tools

Azure DevOps

Job description

Title: Quality Assurance Engineer, PLC Automation
Location: Remote/Hybrid
Term: FTE, Direct Hire

Position Overview

Our client is building the backbone of energy and AI infrastructure powering grid-safe data centers and mission-critical facilities. The company supplies and operates hyperscale power systems that solve the toughest resilience challenges, delivering custom solutions for AI data centers, mission-critical facilities, and front-of-the-meter assets. Our client recently announced a 5GW partnership, with 3GW currently under construction across multiple hyperscale data center campuses. With patented technology and proprietary software, our client develops projects worldwide that set new benchmarks for resilience.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