The DLMS/COSEM specification

The DLMS UA coloured books

The specification as described in the DLMS UA coloured books

IEC standards

International Standards for electricity metering

CEN standards

International Standards for heat/cooling, gas and water metering

Specification maintenance

Specification maintenance process. List of  proposed and approved amendments.

Q/A

Questions and answers concerning the specification

The DLMS UA coloured books

The DLMS/COSEM specification is fully described in the DLMS UA coloured books:

• the Blue book describes the COSEM meter object model and the object identification system
• the Green book describes the three layer, connection oriented, HDLC based protocol stack to transport the model
• the Yellow book treats all the questions concerning conformance testing

The books are available for all members of the DLMS UA free of charge. Excerpts of the books are  publicly available.

View full version of the Blue Book (8th ed.)

View full version of the Green Book (6th ed.)

View full version of the Yellow Book (3rd ed.)

DLMS UA books - document history

DLMS UA books - corrigenda

The specification became an International Standard for electricity, heat/cooling, gas and water metering.

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International standards for electricity metering

For electricity metering, IEC TC13 WG14 has established the IEC 62056 series of standards: Electricity metering - Data exchange for meter reading, tariff and load control.

• IEC 62056-42: Physical layer services and procedures for connection-oriented asynchronous data exchange
• IEC 62056-46: Data link layer using HDLC protocol
• IEC 62056-47: COSEM transport layers for IPv4 networks
• IEC 62056-53: COSEM Application layer
• IEC 62056-61: Object identification system (OBIS)
• IEC 62056-62: Interface classes

In addition IEC 62056-21: Direct local data exchange (3d edition of IEC 61107) describes how to use COSEM over a local port (optical or current loop)

The standards can be purchased from the National Committees of the IEC or from the IEC Webstore directly.

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International standards for heat/cooling, gas and water metering

For the metering of heat/cooling, gas and water metering, CEN TC 294 has established the International Standard EN13757-1: Communication system for and remote reading of meters - Part 1: Data exchange

The standard can be bought from the National Committees of CEN.

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Maintenance of the DLMS/COSEM specification

The DLMS UA regularly maintains the specification to meet new requirements and to incorporate practical experience gathered by using the specification.

Any user of the DLMS/COSEM specification may propose an amendment.

Proposed amendments  are discussed and approved by the Working Group Maintenance.

Approved amendments are regularly added to the DLMS UA coloured books.

IEC and CEN standards are amended according to their maintenance schedule.

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Questions and Answers

Find Questions and Answers concerning the DLMS/COSEM specification.

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