PLC Testing Engineer

L&T Technology Services; Bengaluru; On-site; INR 1,000,000 - 1,500,000; Full time

Job summary

L&T Technology Services is looking for a Senior PLC Firmware Test Engineer to validate firmware used in power plant controllers. In this role, you will ensure functional correctness and performance of critical processes in thermal, hydro, and renewable power plants.

The ideal candidate has 5-7 years of experience, strong PLC firmware testing skills, and the ability to mentor junior engineers. Responsibilities include executing various testing strategies and collaborating with cross-functional teams.

Qualifications

• 5-7 years of experience in validating PLC firmware.
• Hands-on exposure to power plant controllers.
• Strong analytical and debugging skills.

Responsibilities

• Analyze requirements and firmware design documents.
• Prepare and review test strategy and plans.
• Execute functional, integration, and stress testing.
• Conduct Hardware in the Loop (HIL) testing.
• Guide and mentor junior engineers.

Skills

PLC firmware testing

Power plant controllers

Ladder Logic

Function Block Diagram (FBD)

Structured Text (ST)

Test documentation

Tools

JIRA

Azure DevOps

Job description

We are seeking a Senior PLC Firmware Test Engineer with strong experience in validating PLC firmware used in power plant controllers. The role involves testing firmware that controls critical power generation processes, ensuring functional correctness, real-time performance, safety, and regulatory compliance.

The candidate will work closely with firmware developers, control engineers, and system architects to validate controllers used in thermal, hydro, gas, or renewable power plants.

Experience: 5-7 Years

Key Responsibilities

• Analyze power plant controller requirements, functional specifications, and firmware design documents
• Prepare and review test strategy, test plans, and test cases for PLC firmware
• Execute functional, integration, system, regression, and stress testing
  • Control logic and sequencing
  • Interlocks, permissives, and alarms
  • Start up, shutdown, and emergency operating scenarios
  • Fault handling and fail safe behavior
• Perform real-time testing for scan cycle behavior, I/O response, and timing constraints
• Conduct Hardware in the Loop (HIL) and bench level testing using real PLC hardware
• Validate controller behavior for Boiler, Turbine, Generator, and Balance of Plant (BoP) systems
• Test industrial communication protocols, including:
  • Modbus RTU / TCP
  • PROFINET
  • EtherNet/IP
• Identify, log, and track defects using JIRA / Azure DevOps, and support root cause analysis
• Collaborate with control, firmware, and hardware teams to resolve issues
• Support Factory Acceptance Testing (FAT), Site Acceptance Testing (SAT), and customer audits
• Prepare test execution reports, defect metrics, and test closure documentation
• Guide and mentor junior engineers in PLC and power domain testing

Mandatory Technical Skills

• Strong experience in PLC firmware or controller testing
• Hands-on exposure to power plant controllers
• Knowledge of PLC programming languages:
  • Ladder Logic
  • Function Block Diagram (FBD)
  • Structured Text (ST)
• Understanding of:
  • Redundancy and failover concepts
  • Alarm and diagnostic mechanisms
• Strong test documentation and defect management skills
• Understanding of power generation processes:
  • Start up and shutdown sequences
  • Interlocks and protection logic
• Familiarity with safety critical control behavior

Good to Have Skills

• Knowledge of IEC standards:
  • IEC 61131
  • IEC 61508 (Functional Safety)
• Basic scripting or automation using Python
• Experience with certification, compliance, or regulatory testing
• ISTQB / Embedded / Automation testing certification

Soft Skills

• Strong analytical and debugging skills
• Ability to communicate effectively with cross functional teams
• High attention to quality and detail
• Ownership mindset and ability to work in safety critical environments
• Mentoring and technical guidance capability