标准摘要
[中文适用范围]： 适用于具有模拟指示的频率计以及与其一起使用的不可互换附件。第四版取消并取代了第三版。 [外文原描述]： Applies to direct acting indicating frequency meters, and to non-interchangeable accessories used with frequency meters.
英文名称Direct acting indicating analogue electrical measuring instruments and their accessories. Part 4: Special requirements for frequency meters