BS 5164:1975

Cooperating organizations
Foreword
Specification
1. Scope
2. Definitions
3. Classification
4. Permissible intrinsic errors and reference
    conditions for instruments related to the
    measured quantity
5. Permissible intrinsic errors and reference
    conditions related to time-keeping
6. Permissible intrinsic errors and reference
    conditions for accessories
7. Permissible limits of variations
8. Permissible limits of variations for accessories
9. Electrical and mechanical requirements of
    instruments and accessories
10. Constructional requirements for instruments and
    accessories
11. Markings and symbols for instruments and accessories
12. Categories of test
Appendix
A. Concepts
Tables
1. Limits of intrinsic error of instruments related to
    the measured quantity expressed as a percentage of
    the fiducial value
2. Preconditioning of instruments
3. Reference conditions for the influence quantities
    related to the measured quantity
4. Additional reference conditions related to the
    measured quantity for recording instruments
5. Limits of intrinsic error related to time-keeping
    expressed as a percentage of the true elapsed time
6. Reference conditions for the influence quantities
    related to time-keeping
7. Limits of intrinsic error of an accessory expressed
    as a percentage of the fiducial value
8. Normal values of the limits of the nominal range
    of use and allowable variation expressed as a
    percentage of the measuring class index
9. Variation due to mounting on a ferromagnetic panel
10. Normal values of the limits of the nominal range of
    use related to time-keeping
11. Value of test voltage
12. Examples of marking related to the reference
    conditions and nominal ranges of use for instruments
    and accessories
13. Symbols for marking instruments and accessories
14. Examples of limits of effective range and fiducial
    values
Figures
1. Common mode test circuits
2. Effective range 8 A to 50 A
3. Effective range 80 V to 110 V
4. Effect of temperature
5. Effect of temperature
6. Effect of frequency

Defines and classifies instruments using a null balance method and needing an auxiliary electrical supply. Permissible intrinsic errors, reference conditions and variations for measured quantity and time-keeping for recording instruments. Also electrical, mechanical, constructional and marking requirements.

1.1 This British Standard specifies requirements for indirect-acting electrical instruments using a null balance method which need an auxiliary electrical power supply.

These instruments may indicate the value of the measured quantity or record the value of the measured quantity as a function of time. Instruments may combine both these functions.

1.2 This standard also applies to electrically operated measuring equipments, provided that the electrically operated measuring instrument (receiver) only is considered and that the relationship between the non-electrical and the electrical quantity is known.

1.3 This standard does not apply to:

1. devices comprising a direct-acting indicating and/or recording instrument energized by a measuring amplifier;
2. electrically operated measuring equipment when the relationship between the non-electrical and the electrical quantity is not known;
3. control apparatus even though it includes indicating or recording instruments;
4. indirect-acting electrical instruments in which the measured quantity is presented in the form of digits, codes, punched cards, etc.;
5. position follower instruments;
6. recording instruments in which the chart movement is a function of a quantity other than time;
7. integrating instruments or auxiliary integrating devices incorporated in instruments within the scope of this standard.

1.4 This standard does not contain requirements for protection against environmental conditions.

1.5 This standard does not specify requirements concerning dimensions of instruments or detailed requirements concerning terminal markings and diagrams of connection.

NOTE The titles of the British Standards referred to in this standard are listed on the inside back cover.