Stability evaluation of high-precision multifunction instruments for traceability transfer

In the traceability transfer process from the national standards of the Ist ituto Elettrotecnico Nazionale "Galileo Ferraris" (IEN) to standards of cal ibration laboratories accredited by Servizio di Taratura in Italia (SIT), t he use of high-precision multifunction instruments, in particular digital m ultimeters (DMMs), as reference standards turned out to be a good transfer method. In fact, their use provides swift and less expensive transfer at an uncertainty level comparable to that one obtained using high-precision ind ividual standards, such as 10 V de voltage standards, standard resistors, o r ac/dc transfer standards. In this paper, it is described how this transfer process is performed and w hat results are obtained.