approach combining associated measuring instruments (VCD and VCDD) and an energy calculator (EC) of the energy conversion device (ECD) which are verified and approved separately and conditions for the matching of the associated measurement instruments which are verified appropriately, moodullähenemisviis, mis ühendab omavahel kaasmõõtevahendid ja energiamuundurseadme energiaarvesti, ja mis on kontrollitud ja eraldi heaks kiidetud ning asjakohaselt tõendatud mõõtevahendite sobitamise tingimustel