Skip to content
DRAFT⚠OIML SMART pilot programme · internal use only · all documents and specifications are drafts and may change without notice
OIML SMART

Tier 0, the concept (one hour)

The whole system in one sitting: the eight terms, the three claim forms, and where any fact lives.

Tier 0, the concept (one hour)

The whole system in your head, in one sitting. Read this page slowly; at the end you will be able to say what the system is, why it is shaped this way, and where any fact lives. Everything after this is depth on these same ideas.

The eight terms

Every model in this world, a load cell, a Recommendation, a certification program, is described with exactly eight terms. Three relations and five sorts of thing:

  • IS, identity: what a thing is. The truths that individuate it (this is the same entity as before; it is a member of that kind). Not a property among properties: lose it, and the thing stops being that thing at all.
  • HAS, possession: what a thing holds. A property is the slot (mass, owner); a value is what fills the slot today (500 kg, ACME). Properties vary; values are read now.
  • DOES, behavior: what a thing does. A transition is a rule (input → transform → output); transitions compose, and the composite is a transition. A process is a transition reified as an object, so it can have an identity, properties, and values of its own (which run is this? started when? where is it now?).

That is the entire vocabulary. Formally it is proved closed (no operation escapes it), complete (every descriptive claim , identity, attribution, transformation, factors through it), and extensible (new domains enter as content, never as new primitives).

The three claim forms

Every descriptive claim about anything is one of three forms, and that is why requirements, tests, and forms are secondary models, never peers of the subject:

  • Requirements are constraints on a subject’s IS/HAS/DOES (“the temperature range shall be X to Y”).
  • Tests are processes that probe a subject’s IS/HAS/DOES to produce evidence (“run test procedure A at X, then at Y”).
  • Forms are interfaces for recording that evidence (“at 20 °C this input gave this output”).

The subject, the measuring instrument, is primary. Everything else is derived from it.

The three layers of the digital twin

Physical device
   ⇕  representation (any shape)
FULL DIGITAL TWIN   — the manufacturer's complete representation
   ⇕  PROJECTION, declared by the standard's governed aspect set
PRIMMEL TWIN      — only what the standard governs
   ⇕  fidelity proof (served ≡ physical within δ + freshness)
TWIN CERTIFICATION — certifies the projection, never the full twin

A manufacturer’s twin can be arbitrarily rich, physics, telemetry, history, diagnostics. The Primmel twin is a tailored projection of it: only what the standard declares it governs (the governed aspect set, in the Recommendation’s own model). The manufacturer’s internal richness stays private; the projection is what you are allowed to read.

Why not an admin shell

The industrial mainstream (Siemens et al.) calls a device interface an “admin shell”, a standardized set of verbs: commands you may invoke. The Primmel twin is not that. It is a governed state projection: you read what the standard declared it governs. The decisive difference is who designs the interface: an admin shell is designed per vendor (it drifts per vendor); a Primmel twin is derived from the standard, the interface is generated from the governed aspect set, so every compliant twin has the same shape, and a certification engine can rely on it. You cannot certify against an interface that drifts.

The one rule that keeps it honest

The Primmel packages are the single source of truth. Everything downstream, the data trees, the generated code, the screens, is a generated artifact, proven byte-identical to the packages by a drift guard on every gate. You never edit a generated artifact; you edit the package and regenerate.

The tier-0 assessment

Explain, in your own domain (your instrument, your device, your standard):

  1. What is the subject, and what are its IS / its HAS / its DOES?
  2. What would its full digital twin contain that its Primmel twin must not serve?
  3. Who declares the governed aspect set, and why must it be the standard, not the vendor?

If you can answer all three with a straight face, tier 0 is done. Tier 1, the hands-on makes them physical.