DIN EN 60051-7-1991 直接显示的模拟电器测量仪及附件.第7部分:多功能测量仪的特殊要求
Direct acting indicating analogue electrical measuring instruments and their accessories; part 7: special requirements for multi-function instruments (IEC 60051-7:1984, edition 4); german version EN 60051-7:1989