scope:

Part 4 of the standard applies to direct acting indicating analogue frequency meters.

This part also applies to non-interchangeable accessories (as defined in Sub-clause 2.1.15.3 of Part 1) used with frequency meters.

This sub-clause of Part 1 does not apply to frequency meters.

This standard also applies to instruments and accessories having electronic devices in their measuring and/or auxiliary circuits.

This standard does not apply to special purpose instruments which are covered by their own IEC standards.

This standard does not apply to special purpose devices which are covered by their own IEC standards when they are used as accessories.

This standard does not contain either requirements for protection against environmental conditions or the relevant tests. However, when necessary, and then only by agreement between the manufacturer and the user, tests to approximate the conditions of use may be selected from I EC Publication 68 : Basic Environmental Testing Procedures, to prove protection against environmental conditions.

This standard does not specifi requirements concerning dimensions of instruments or accessories (for the former, see IEC Publication 473: Dimensions for Panel-mounted Indicating and Recording Electrical Measuring Instruments).