Controls & PLC engineering
Ladder and structured-text development for Allen-Bradley, Siemens and Omron platforms, HMI design, safety circuits and UL 508A panel specification.
Milpitas, California
Founded 2016
UL 508A panel partners
Automation engineering that makes production lines predictable
Sigma Delta Engineering designs, integrates and supports the control systems behind packaging, electronics and food-processing lines. We are a small, senior team — the engineer who scopes your project is the engineer who commissions it.
No obligation. Most first calls last 20 minutes and end with a written summary.
120+Commissioned projects
9Serving Bay Area plants
31%Average downtime reduction
24hResponse commitment
Who we are
A controls studio, not a staffing agency
Sigma Delta Engineering LLC was founded in Milpitas by Mellina La Rocca after fifteen years spent on plant floors in California and São Paulo. The premise was simple: manufacturers deserve controls engineers who stay through commissioning, document what they build, and hand over a system the in-house maintenance team can actually own.
We keep the team deliberately small. Every engagement is led by a senior engineer, scoped in writing before work starts, and delivered with drawings, tested code and an operator manual — never a black box.
- Fixed-scope proposals with named deliverables and dates
- Source code and documentation handed over, unencrypted, at close-out
- Vendor-neutral: we specify what fits the plant, not what we resell
- Bilingual delivery in English and Portuguese for cross-border programmes
What we do
Five services that cover the life of a line
From the first electrical drawing to the dashboard your plant manager reads on Monday morning. Engage us for one phase or all five.
Line & robot integration
Mechanical and electrical integration of new cells into existing lines, including vision, servo motion, conveyance handshakes and OPC UA connectivity.
Manufacturing data & OEE
Historian design, SQL data models and reporting so availability, performance and quality are measured the same way on every shift.
Automation & safety audits
Independent review of code, arc-flash labelling, E-stop categories and cyber exposure, delivered as a prioritised remediation plan.
Commissioning & retainer support
On-site start-up, operator training and a monthly retainer with guaranteed response windows for changeovers and faults.
Documentation recovery
Reverse-engineering of undocumented legacy machines into current drawings, I/O schedules and maintenance procedures.
Why clients stay
Downtime is a data problem before it is a mechanical one
Most plants we walk into already know which machine hurts. What they lack is evidence: how often it stops, for how long, and which upstream event triggers it. Our first move is almost always instrumentation — then we fix the right thing once, instead of the wrong thing three times.
| Unplanned stops per shift | 7.4 → 4.1 |
|---|---|
| Mean time to repair | 38 min → 21 min |
| Changeover time | 52 min → 33 min |
| Documented I/O coverage | 44% → 100% |
Figures are averages from client-reported production data, 2023–2025. Results vary by plant; we will tell you honestly when a target is not realistic.
How it goes
A predictable five-stage engagement
Discovery call
Twenty minutes on the phone. We ask what stops, when, and what has already been tried, then send a written summary the same day.
Plant walk & assessment
A half-day or full-day on site. We photograph panels, pull existing drawings, log faults and speak to the operators who run the line.
Fixed-scope proposal
Deliverables, exclusions, milestones, price and schedule in one document. No hourly surprises.
Build & factory test
Code, panels and HMI screens developed and simulated off-line, then reviewed with your team before anything touches production.
Commissioning & handover
Start-up during a planned window, operator training, as-built drawings, source code and a 30-day stabilisation period.
In their words
What plant teams tell us afterwards
“They found a handshake timing fault our previous integrator had papered over for two years. The line has run three quarters without an unplanned stop on that station.”
“The documentation package alone was worth the fee. Our maintenance techs stopped calling the vendor for every alarm because they can finally read the drawings.”
“Mellina scoped the job honestly and told us which half we did not need yet. That is rare and it is why we came back for phase two.”
Client names withheld under standard confidentiality terms. References available on request during proposal stage.
Platforms we work with daily
Allen-Bradley / RockwellSiemens TIA PortalOmron Sysmac
Beckhoff TwinCATIgnition SCADAWonderware
Cognex VisionFANUCUniversal RobotsOPC UA / MQTT
Tell us about the line that keeps you awake
Send drawings, a fault log or just a description of the problem. You will get a written response from an engineer — not a sales script — within one business day.