Controls Engineer, PLC Programming

Fluidstack; San Francisco (CA); On-site; USD 200,000 - 250,000; Full time

Benefits offered by this job

Stock options

Job summary

Fluidstack in San Francisco designs frontier compute infrastructure and seeks a Controls Engineer to develop and test template PLC programs for data center gear, ensuring cross‑hardware compatibility and robust operation.

You will work with Siemens, Codesys, and virtualized PLCs, wiring IO and sensors, and debugging in a lab to validate sequences before live deployment.

Qualifications

• You’ve written and tested PLC programs for mechanical equipment and real hardware, not only in simulation.
• You’ve programmed across more than one PLC platform (Siemens, Codesys, or virtualized environments).
• You’ve turned a sequence of operations into working PLC code and you’ve caught gaps in an SOO before they reached the controller.
• You’ve wired PLCs, IO, and sensors yourself, tracing faults to the physical layer when needed.
• You write structured, reusable code that can be reused by the next engineer.
• You test against failure and edge cases in the lab.
• Bonus: BACnet/Modbus, IEC 61131-3 languages, hardware-in-the-loop testing.

Responsibilities

• Develop and test template PLC programs for data center equipment across various hardware.
• Write portable code across Siemens, Codesys, and virtualized PLCs.
• Develop and tune sequences of operations and implement SOOs in PLC code.
• Install and wire PLCs and sensors in a lab to validate programs before live deployment.
• Debug programs against real IO and failure conditions on the bench.

Skills

PLC programming

Siemens PLC

Codesys

Structured code

Hardware debugging

Field wiring

Real hardware testing

SOO review

Tools

BACnet

Modbus

IEC 61131-3

Virtualized PLC testing

Job description

About Fluidstack

We exist to make humanity more free. For most of human history, you farmed or you starved. Technology gave people more time for the things they wanted to do, instead of things they had to do. Powerful AI will be the biggest lever for human choice we've ever built - but only if models are aligned with what humanity actually wants. There are groups building AI who don't share these goals. Whoever deploys frontier compute infrastructure fastest will decide whether AI expands human freedom or shrinks it.

How We Operate

• Extreme ownership. Full autonomy. Own things end to end often taking on scope outside your core role without being asked to get things done.
• Velocity. We drive everything forward as fast as possible.
• First principles. Challenge every assumption. Zero analogy thinking, no egos, the best idea wins.
• Love of the game. The frontier of AI is the most interesting problem of our time. We put in long hours at high intensity to push the frontier forward.

The Controls Team

Examples of key problems the team is working on

• Deliver the controls behind 50GW+ of data centers this decade.
• Own real-time load control and MEP and behind-the-meter integration.
• Automate Level 4 and Level 5 commissioning.
• Drive autonomous, robotic deployment.

Role Scope

• Develop and test template PLC programs for the standard mechanical equipment across every data center, chiller skids, fan wall units, CRAHs, and the rest, so one validated program deploys fleetwide instead of being rebuilt site by site.
• Write portable code across mixed PLC hardware, Siemens, Codesys, and virtualized PLCs, so a program built once runs regardless of the controller underneath it.
• Develop and tune sequences of operations with the controls and mechanical teams, then implement those SOOs directly in PLC code.
• Install and wire PLCs and sensors in a lab environment, standing up real hardware to validate programs before they ever run on live equipment.
• Debug programs against real IO and failure conditions on the bench so field commissioning becomes a verification step, not a debugging session.

What We're Looking For

The below is a starting point. We always make space for exceptional people, so if you don’t fit this role exactly, tell us where you would.

• You’ve written and tested PLC programs for mechanical equipment, chillers, air handlers, pumps, or similar, and watched them run on real hardware, not only in simulation.
• You’ve programmed across more than one PLC platform, Siemens, Codesys, or virtualized environments, and you don’t treat one vendor’s toolchain as the boundary of what’s possible.
• You’ve turned a sequence of operations into working PLC code, and you’ve caught the gaps and contradictions in an SOO before they reached the controller.
• You’ve wired PLCs, IO, and sensors yourself, and you’ve traced a fault down to the physical layer when a program that looked right on screen misbehaved on the bench.
• You write structured, reusable code that the next engineer can read, so the templates you build get reused rather than rewritten.
• You test against failure and edge cases, not just the expected path, and you find the problems in the lab instead of in a running data center.
• Bonus: Data center mechanical systems (chiller plants, CRAH/CRAC, fan wall units). Structured Text and the IEC 61131-3 languages. BMS or SCADA integration over BACnet and Modbus. Hardware-in-the-loop or virtualized PLC testing.

Compensation

$200,000 - $250,000 per year, depending on experience, skills, qualifications, and location. Offers equity in the form of stock options. We are committed to pay equity and transparency.

Equal Employment Opportunity Statement

Fluidstack is an Equal Employment Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, national origin, sexual orientation, gender identity, disability and protected veterans’ status, or any other characteristic protected by law. Fluidstack will consider for employment qualified applicants with arrest and conviction records pursuant to applicable law.