Stability evaluation of high-precision multifunction instruments for traceability transfer

In the traceability transfer process from the national standards of the Istituto Elettrotecnico Nazionale "Galileo Ferraris" to standards of calibration laboratories accredited by Servizio di Taratura in Italia, the use of high-precision multifunction instruments, in particular digital multimeters, 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 individual standards, such as 10 V DC voltage standards, standard resistors, or AC/DC transfer standards. In this paper, how this transfer process is performed and what results are obtained, are described.