QA Enginer, PLC Automation

ASCENDING; United States; Hybrid; USD 110,000 - 150,000; Full time

Job summary

ASCENDING is seeking a Quality Assurance Engineer focused on PLC automation. You will design and execute tests for PLC-based control systems, develop Python-based test automation, and validate communication protocols across Siemens platforms.

This role blends software testing with industrial automation to ensure reliable energy data center infrastructure. You will collaborate with controls engineers, create test plans, and maintain automated frameworks (pytest), including HIL/SIL testing where

Qualifications

• Bachelor-level degree in software/quality engineering or related field.
• 5+ years hands-on PLC programming and testing (Siemens platform).
• 5+ years building/maintaining automated test frameworks (pytest or equivalent).
• 3–5 years Siemens TIA Portal experience for PLC development/diagnostics.
• Experience designing functional and integration tests, including defect tracking.

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, ST) on Siemens S7-1200/1500.
• Collaborate with controls engineers to define acceptance criteria and validate requirements.
• Identify, document, and track defects; lead root cause analysis for critical failures.
• Conduct HIL/SIL testing where applicable.
• Produce test plans, reports, and traceability matrices aligned with release timelines.

Skills

PLC programming

Python test automation

Automated test frameworks

Functional testing

Integration testing

Education

University degree in Software Engineering/CS/Quality Engineering

Tools

Siemens TIA Portal

pytest

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