A technique for electromagnetic interference measurements on instruments

The aim of this paper is to highlight the problems that arise when the immu nity of measurement instruments to power line voltage disturbances has to b e evaluated. The lack of an international product standard puts at the user 's disposal only some basic standards which, in giving only general criteri a for test result classification, make it difficult to choose suitable acce ptance criteria and, consequently, to plan a proper set of tests, especiall y for very complex instruments. After an introduction on the state of art of electromagnetic compatibility (EMC) international standards, a measurement technique adopted by the autho rs to evaluate the immunity of complex instruments to conducted disturbance s is presented. Finally, experimental tests carried out on VXI instruments are given and discussed exhaustively.