Skip to content
SMART Measuring Instruments

SMI · 05

Continuous Compliance

In this page: the monitor, the verdict engine, the evidence streams, and the re-judgment path. What continuous compliance means for an instrument owner and for an authority.

1. The monitor

A certified twin is watched, not trusted. The monitor binds the twin endpoint and cycles on a schedule and on state change: it reads the served registers, and it judges each read against the instrument’s certified promises (the accuracy envelope, the declared characteristics, the operational conditions). The cycle produces verdicts, and the verdicts accrue into the instrument’s compliance stream.

The monitor’s rules are the Recommendation’s own: the same constraints the type evaluation judged at certification time, now judged against live service.

2. What a judgment can say

The verdict engine’s live vocabulary is deliberately three-valued:

  • Pass. The served value holds the promise, with the serve-time freshness proven.
  • Fail. The served value violates the promise (a drift beyond the envelope, a characteristic out of its declared range).
  • Indeterminate. The engine cannot judge: the twin stopped serving, serves stale, or the reference channel’s provenance is insufficient. Indeterminate is not a fail; it is the honest answer when the basis is missing, and it carries health events so the outage is visible.

A silent pass is the one outcome the engine refuses: a value that cannot prove its freshness is never reported as passing.

3. The evidence trail

Every judgment leaves a record, and the records chain:

  • Probe records (from twin certification): the channel, the reference value, the served value, the delta, the verdict.
  • Verdict stream (from the monitor): each cycle’s judgment with its basis (the served registers it judged from) and the definition version it judged with.
  • Health events (from the endpoint): outages, staleness, recovery.
  • Lifecycle events (from the certificate): flags, suspensions, reinstatements, re-judgments.

An auditor can walk the chain from the clause, through the certified promise, to last quarter’s verdict history, to this morning’s batch records. The trail is the platform’s runtime, not a report generated after the fact.

4. Re-judgment

When the basis changes (a repaired endpoint, a corrected register, a renewed probe), the chain re-judges: the same promises, the same engine, the corrected evidence. The re-judgment is recorded as its own event with provenance, and the certificate’s lifecycle reflects it (suspension, reinstatement). Nothing is edited silently; the history shows both the original judgment and its correction.

5. For the authority

For a legal-metrology authority, continuous compliance is the point of the SMART instrument: certification stops being a point-in-time act and becomes a surveilled state. The authority reads the same verdict chain the instrument owner sees, judges from the same definitions, and can re-run any judgment from its recorded basis.