controls Engineer

GCS Recruitment; Boston (MA); On-site; USD 90,000 - 120,000; Full time

Job summary

GCS Recruitment is seeking a Controls Software Engineer to join a high-impact engineering team in Boston. The focus will be on maintaining and improving a fleet of over 1,000 robotic workcells, ensuring operational reliability.

This hands-on role involves identifying bugs, conducting hardware tests, and authoring essential documentation. Candidates should have strong Structured Text development experience and be willing to work on-site in either Seattle or Boston. A mid-to-senior level of experience is preferred, reflecting the urgency of the role.

Qualifications

• Strong IEC 61131-3 Structured Text development experience is required.
• Real controls / PLC software development background is essential.
• Ability to independently own and deliver tasks is necessary.

Responsibilities

• Investigate and resolve bugs in the deployed application.
• Diagnose issues using telemetry and logs.
• Write and validate control code on physical test machines.

Skills

IEC 61131-3 Structured Text development

Controls / PLC software development

Hands-on experience with industrial hardware

Technical writing

Tools

TwinCAT

CODESYS

Job description

Controls Software Engineer - Structured Text

Industrial Robotics Program | Contract Engagement | Seattle, WA or Boston, MA (On-Site) | Immediate Start

About the Opportunity

We are hiring a Controls Software Engineer to join a high-impact engineering team supporting a large-scale industrial robotics program at one of the world's leading e-commerce and logistics companies. The program operates a fleet of over 1,000 robotic pick-and-place workcells across global fulfillment centers today, scaling to 5,000-6,000 machines by 2027.

This is a hands-on, technically deep contract engagement with strong likelihood of extension. You will work inside a small, tight-knit team of controls and software engineers responsible for keeping the deployed fleet running reliably and improving its performance at scale.

The Program

The product is a Transfer Cartesian Cell (TCC) - an 8-axis, servo-driven Cartesian pick-and-place robotic workcell. It integrates with mobile floor robots inside fulfillment centers: the floor robots deliver pods of totes to the cell, and the TCC reaches in, retrieves the totes, and places them onto conveyance systems for downstream handling.

The deployed fleet runs on an IEC 61131-3 control platform on Linux-based industrial PCs. The architecture is mature - this is not greenfield development. Your focus is hardening the deployed fleet, reducing faults, and closing performance gaps while a parallel next-generation platform is developed alongside.

What You’ll Be Doing

Sustainment and Fault Reduction (80-90% of the work)

• Investigate and resolve bugs and faults in the deployed control application running across 1,000+ machines in the field
• Diagnose issues using machine telemetry, logs, alarm history, and operational data; drive fixes from root cause through deployment
• Some fixes require feature-level rework - rethinking modules to remove complexity and improve reliability rather than patching

Rate, Throughput, and Performance

• Address rate gaps and workcell throughput shortfalls - the team is currently behind aggressive performance targets, so your impact is visible quickly
• Work across the servo control layer, motion orchestration, and state handling to close performance gaps
• Introduce targeted improvements that make the machines faster and more reliable at fleet scale

Lab and Hardware Testing

• Write, test, and validate control code on physical test machines located on-site
• Work hands-on with real hardware - servos, drives, sensors, vision systems, and conveyance components
• Define test cases and provide QA context for downstream validation

Documentation and Change Management

• Author Management of Change Memos (MCMs) detailing each change going to the field
• Drive stakeholder alignment and approval across deployment, operations, hardware, and field support before changes ship fleet-wide
• Create runbooks, troubleshooting guides, and hardware failure documentation

What We’re Looking For

Must-Haves

• Strong IEC 61131-3 Structured Text development experience - this is the core requirement
• Real controls / PLC software development background
• Ability to independently own tasks, execute, and deliver
• Hands‑on experience with industrial hardware - servos, drives, sensors, motion systems
• Willingness to work on‑site in Seattle or Boston

Strongly Preferred

• TwinCAT experience - aligns directly with the platform and ways of working
• CODESYS experience - ideal, though not required
• Servo control, motion, Cartesian, or pick‑and‑place workcell background
• EtherCAT or industrial fieldbus depth
• Experience supporting fleet‑scale or production systems, not just single‑machine commissioning
• Strong technical writing - runbooks, change memos, troubleshooting guides

Not a Fit

• Ladder‑logic‑only backgrounds without Structured Text
• Candidates unable to work on‑site in Seattle or Boston

Experience Level

We are open to a range of experience levels. Mid‑level engineers with 3-5 years are welcome provided they can own tasks and deliver independently. Senior engineers who can plug in immediately are equally welcome. What matters is demonstrated Structured Text capability and the ability to execute.

Location and On‑Site Requirement

This role is on‑site in Seattle, WA or Boston, MA. Test hardware lives in the lab and close collaboration with the team is essential, particularly in the first few months. For candidates committed to relocating, a short‑term arrangement (e.g., weekly travel for the first ~2 months while relocation is completed) can be documented as part of the contract.

Engagement Details

Location: Seattle, WA or Boston, MA - on‑site

Contract: Milestone‑based contract engagement with strong likelihood of extension

Start: As soon as possible - interviews happening now

Hours: Full‑time

How to Apply

Send your resume with a brief note covering your Structured Text experience (and the platforms you’ve used it on - CODESYS, TwinCAT, Allen‑Bradley, Siemens, etc.), the types of machines and systems you’ve programmed, and your willingness to work on‑site in Seattle or Boston. We’re moving quickly - candidates who can demonstrate real Structured Text depth will be prioritized.

GCS is acting as an Employment Business in relation to this vacancy.