This guide specifies principles for determining the use of units in digitised communication of machine-readable data. These principles form the basis for all applications that transmit or require measurement data according to the specifications of the Système International d'Unités (SI). Basic principles for harmonised, clear, easy to understand and secure digital communication of metrological data are defined for real, complex, vector and constant quantities. The metadata model described is essential for the exchange of metrological information in all fields of Information and Communication Technologies (ICT). In terms of content, the model takes into account essential international metrology guidelines and standards. For the first time, in conjunction with the globally established SI, measures are defined which are essential for an easy, secure, harmonised and unambiguous exchange of metrological data. The handling of non-SI units and the requirements for conversion between SI and non-SI quantities are taken into account. In addition, a classification for the suitability of metrological data for interoperability and machine readability is made (medal system). The classification results from the use of SI units as defined in the 9th edition of BIPM's SI brochure. This dokument is deliverable D1 of the EURAMET EMPIR project 17IND02 (SmartCom, WP1).

The development of the uniform metadata format for the exchange of measurement data in ICT applications is part of the research project EMPIR 17IND02 (Title: SmartCom). This brochure is the result of Deliverable 1. The project was funded by the EMPIR programme co-financed by the participating countries and by the European Union's Horizon 2020 research and innovation programme.

{"references": ["EMPIR 17IND02 (SmartCom): Website of the research project, https://www.ptb.de/empir2018/smartcom/home/ (accessed October 2019)"]}