scope:

This Recommandation applies to direct recording electrical measuring instruments, which are used for recording the instantaneous, effective or mean values of one or more measured quantities as a function of time. It refers to strip, drum and disc recording instruments, namely: ammeters; voltmeters; single-phase wattmeters, varmeters and phasemeters; polyphase wattmeters, varmeters and phasemeters; frequency meters; ohmmeters. The Recommendation also applies to electrically measuring instrument (receiver) only is considered, and that the relationship between the non-electrical quantity and the electrical one is known.