Interoperability is a key requirement for modern systems for data exchange. An important element of interoperability is the correct implementation of the relevant standard, which can be proven by conformance testing.

Conformance requirements can be formulated as abstract test cases, which, when implemented in software called a Conformance Test Tool (CTT) and properly parameterised, become executable test cases.

The DLMS UA provides a CTT and a Certification scheme since the publication of the IEC 62056 / EN 13757 DLMS/ COSEM standards in 2002. Activities cover designing the abstract test cases, developing the CTT, making it available via commercial arrangements, verifying test reports, issuing certificates and providing technical support.

The system is very lean with minimum administrative requirements. Both self testing and third party testing is possible. Many companies opt for self testing, as in this case the tool can be used during product development, reducing time-to-market and costs. To facilitate this, a powerful log module is available presenting all line traffic in readable form.

The test report and log contains all the essential elements concerning the meter tested and the test conditions:

  • Declarations concerning the configuration of the meter
  • Results of protocol layer tests
  • Results of COSEM object tests: interface class identifier, logical name (OBIS code) and textual name, data types used.

This information is also useful for system integrators. Should any error occur, the CTT provides useful diagnostic information.

The first certificate was issued in September 2002. By end of 2007, 77 certificates had been granted to 20 companies. The list of certified equipment can be found at www.dlms.com/en/conformance

The fourth quarter of 2007 brought several “firsts”. The first meter types developed by Chinese, Indian and Australian manufacturers were successfully tested and certified for DLMS compliance. So far 19 CTT licenses have been purchased, 12 in Europe, one in the Middle East and six in Asia. There are three third party test facilities, one in Europe and three in Asia.

Also a new version of the CTT was released, bringing the tests in line with the latest editions of the Green Book (Ed 6.0) and the Blue Book (Ed 8.0). It is able to test the TCP/IP based profile, and provides deeper testing and more detailed reporting of results. To adapt to the new tool, a transition period is provided.

As the system of OBIS codes is continuously enhanced to cover new applications, the Object definition files containing latest allocations can be downloaded and plugged in the tool in the form of .dat files.

We at the DLMS UA believe, that by making the conformance testing scheme available, system integration costs can be substantially reduced – a very important aspect of mass rollouts of smart metering systems.

Late news just in when this column was delivered was that the first DLMS COSEM compliant gas meter had been certified.

Please contact us for more information or any question about the DLMS User Association at

Pre-de-la-Fontaine 19,
CH-1217 Meyrin-Geneva,
E-mail: dlms@dlms.com,
or visit our website www.dlms.com

Gyözö Kmethy, President Paul Fuchs, General Secretary