Coilmind vs the Siemens Eigen Engineering Agent
Siemens shipped a strong product. It generates LAD and SCL, configures hardware and SINAMICS drives, builds WinCC Unified screens, translates project texts and checks code against your style guide. If you’re an organisation standardised on the Siemens toolchain, it will likely fit you better than Coilmind does.
This page is for everyone else: engineers on V17 or V18, people who can’t commit £1,548 for a year up front, teams working where the internet doesn’t reach, and anyone maintaining STL nobody wants to touch.
Who each one is built for
Look at what Eigen does beyond writing code: SINAMICS drive parameters, motors and encoders, device and module management, mass adaptations across dozens of blocks, style-guide conformance. That is the work of a line builder with a hardware department and a written standard.
The licence tells the same story. One seat covers up to three assigned users, one at a time, managed through an Industry Organization Account — which Siemens describes as one per company. It’s built for an organisation that assigns and reassigns licences as people come and go.
Coilmind is built for the engineer. One person, one licence, one card. The work it’s good at is the work you personally do every week: cloning a block for the twelfth conveyor, reverse-engineering someone else’s logic, translating comments for a client’s HMI, fixing legacy on site.
Neither is the better product. They’re aimed at different people, and everything below follows from that.
The version wall
Eigen requires TIA Portal V19, V20 or V21.
If your machines run on V17 or V18 — and plenty do, because upgrading a working project is a risk nobody takes for fun — Eigen isn’t an option at any price. No lower tier, no legacy mode. The answer is upgrade first.
Coilmind works from V17. If you’re maintaining a 2021 project for a client with no migration plans, that’s the situation it was built for. Straight about the limits: day-to-day testing runs on V19–V21, and a few conveniences — block renaming among them — need V21. On V17 and V18 the core works and the edges are thinner.
This isn’t a gap that closes next release. A cloud assistant tracks the current portal because that’s where the API surface it needs lives. Supporting older versions is a cost somebody has to deliberately carry.
£1,548 before you know if it works
Eigen has one plan and one term: £1,548.16 per seat, billed yearly. There is no monthly option. You get a free month to decide, and then you commit to twelve.
That’s fine if the free month happens to line up with the right kind of work. If you spend it on a commissioning trip, or on a V17 project Eigen can’t open anyway, the window closes and the next entry point is the full year.
Coilmind is €29 a month. If it doesn’t fit how you work, you’re out twenty-nine euros and an evening. Quiet quarter? Drop a tier. Between contracts? Cancel and come back. Nobody to call.
If you’d rather pay for the year, you can — two months free, so €290, €590 or €1,490. The difference is that it’s a choice rather than the only door.
And nobody knows what this category looks like in a year. Committing twelve months to any of it — including to Coilmind — is a bet. Paying monthly means you don’t have to make it.
Two of you, one licence
Eigen’s licence covers three assigned users per seat, but only one can work at a time. If two of you need the agent on a Tuesday afternoon, that’s two seats.
A Coilmind licence covers several machines — two, four or ten depending on the plan — and you can work at the same time. The ceiling is requests per minute, not named seats. For a two- or three-person integrator that’s the difference between one subscription and three.
If you’re consistently hitting the rate limit, that’s the signal to move up a plan. Not to buy another licence.
The legacy problem
Eigen’s published capabilities cover LAD and SCL. STL isn’t in the list.
That’s the format a lot of the painful work is written in — blocks from 2008 that still run a line, that nobody on the team reads any more, and that you inherit with the project. Coilmind reads STL and rewrites it into SCL or LAD. Proving the rewrite behaves the same is a workflow rather than a button: you run the original’s tests against the new version, which needs PLCSIM Advanced — Siemens sells it separately. Whatever can’t translate cleanly, you see — no silent guesses.
If your work is new projects on modern hardware, this section doesn’t matter to you. If your work is keeping other people’s machines running, it may be the only section that does.
Where your project lives
Eigen is a managed cloud service, and Siemens states it ensures full data privacy and sovereignty. For most companies that settles it — it’s Siemens, and they already trust them with the controllers.
Coilmind is a Windows application on your machine. By default requests go through our proxy to our inference providers — DeepInfra and Fireworks, both in the US — so let’s be straight: with the cloud model, the relevant part of your project leaves your PC too. Anyone claiming otherwise about a cloud-model tool is telling you about their control plane, not your data.
The difference is you can switch it off. Run a local model on your own hardware and nothing leaves the machine — on site, in the field, air-gapped. Local models are weaker than cloud ones and how capable depends on your GPU. The block templater is fully deterministic with no model at all, which matters where AI is off the table by policy.
What Siemens does better
Devices and modules, SINAMICS drive parameters, motors and encoders, PROFINET, ECAD-to-project generation. Coilmind does none of it and isn’t planning to.
Eigen creates WinCC Unified devices. Coilmind works inside devices that already exist — it builds screens, items, dynamizations and HMI tags, but it will not add the panel for you. Faceplate types are beyond both of us: Openness cannot create them.
Mass adaptations across many blocks, style-guide enforcement, automatic project documentation. Built for teams with a written standard. Volume discounts start at six seats.
For a large company, buying inside Siemens Digital Exchange against an existing agreement is far less friction than adding a vendor. That’s real, and it has nothing to do with software.
Siemens makes the PLCs, the portal and the API. If Openness changes, they know first. I find out the same day you do.
There’s a support organisation behind Eigen. Behind Coilmind there’s me, answering email.
Is Coilmind right for you?
- ✓you’re on V17 or V18
- ✓you buy your own tools and £1,548 up front isn’t how you buy them
- ✓you want to pay monthly and stop when work is quiet
- ✓two or three of you would share one subscription
- ✓you work where the internet doesn’t reach
- ✓your weeks are spent on blocks, legacy code and translation
- ✓you inherit STL
- —your bottleneck is hardware, drives or PROFINET
- —you need WinCC Unified screens built for you
- —you need style-guide enforcement across a big codebase
- —you have more than a handful of engineers and volume pricing matters more than terms
- —you’re an organisation where staying inside Siemens procurement is worth the difference
Try it against your own project
Fourteen days, no card, twenty-five tasks included. Open a project you already know, ask for something you’d normally do by hand.
Eigen has a free month too. If you’re deciding between them, run both — you’ll know within an afternoon which one fits how you work.
Download Coilmind