Register checklist

Minimum meter reads for village billing · OBIS · VMRS v0.1-draft · NOT a published standard

Operators need a short list of meter values — kWh used, credit left, tamper flags, disconnect state — not a thousand utility registers. This page names that short list. New to Village Metering? Read Overview first.

OBIS (Object Identification System) is how the metering industry names registers — e.g. 1.8.0 always means cumulative active import energy (kWh). DLMS meters implement OBIS codes internally; vendors disagree on which codes they expose and how, not on what the codes mean.

VMRS — the Village Minimum Register Set — is ISV’s draft shortlist of the OBIS keys a village feeder actually needs: import kWh, remaining credit, tamper, disconnect state, clock, and a handful of metrology reads. It is the register appendix for northbound JSON/MQTT at the gateway — roughly ten keys instead of a utility-scale COSEM ICD or MDMS profile. Operators cite VMRS in procurement; integrators map vendor ICDs to the same checklist; gateways publish a VMRS-shaped payload so one HES or MPM integration survives meter OEM changes.

Machine-readable source: vmrs-registers.json · transport contract: northbound-mqtt-v0.1.json.

Northbound JSON/MQTT at the gateway is the interoperability contract. VMRS names which OBIS keys should appear in that payload — mostly tier A codes every DLMS meter already has, plus tier B prepaid and control registers that vary by vendor.

IDIS · companion profile above OBIS

IDIS (Interoperable Device Interface Specification) is not a second naming system for registers and is not VMRS. IEC 62056-6-1 OBIS names COSEM objects. DLMS says how to read them. Those standards still leave options, manufacturer extensions, and media choices. A companion specification picks one configuration so two vendors’ meters actually interoperate. IDIS is that companion-spec layer for DLMS/COSEM smart meters — use-case-driven object models plus a certification label. [1] [2]

Large utilities write that companion spec themselves (ERDF LINKY, Iberdrola PRIME). IDIS was founded so smaller utilities could buy multi-vendor equipment against a shared, tested profile instead of a single OEM’s ICD. Semantic model: COSEM / IEC 62056-6-1 and 62056-6-2. Syntax and security: DLMS/COSEM application layer IEC 62056-5-3. The functional model is kept separate from the wire so a new PLC or IP stack can land without renaming 1.8.0. [1] [2]

November 2021: the IDIS Industry Association (Zug) merged into the DLMS User Association Smart Metering Working Group. Legacy IDIS packages stay supported. New work is Generic Companion Profiles (electricity, heat, water, gas) plus interoperability testing. That is the same “pick the options, then certify” method — now under DLMS UA, not a separate IDIS org. [4] [5]

Sources: [1] Landis+Gyr, IDIS white paper (founding association · Package 1 S-FSK / IEC 61334-5-1 · use cases). [2] Landis+Gyr, IDIS interoperability white paper (2014) — companion spec vs open standard; Package 1 (2011) / Package 2 IP (2013); COSEM IEC 62056-6-1/6-2 + DLMS IEC 62056-5-3. [3] DNV, IDIS certification tests — three packages; P1/P2 new certs closed; Package 3 via DLMS UA. [4] DLMS UA, merger announcement (22 Nov 2021) — IDIS → SMWG; legacy packages + Generic Companion Profiles. [5] DLMS UA HelpDesk, IDIS and DLMS UA (updated 12 May 2025). Related: AC Electricity Smart Meter GCP (post-merger profile; lists prepayment among use cases — not VMRS).

Northbound JSON example

Gateway reads COSEM/OBIS locally, publishes MQTT envelope (northbound-mqtt-v0.1.json):

{
  "schemaVersion": "0.1",
  "ts": "2026-06-22T14:30:00Z",
  "feederId": "feeder-north-paravur-01",
  "gatewayId": "pole-ems-0042",
  "meterSerial": "DDZ1513-88421",
  "registers": [
    { "obis": "1.8.0", "value": 1842.5, "unit": "kWh", "quality": "good" },
    { "obis": "96.8.0", "value": 12.4, "unit": "kWh", "quality": "good" }
  ]
}

northbound JSON · vmrs-registers.json