BS 90 75th Edition, February 28, 1975
Specification for Direct-acting electrical recording instruments and their accessories
Includes all amendments and changes through Reaffirmation Notice , June 1, 2016
Published By:British Standards Institution (BSI)
Defines and classifies accuracy classes, methods of determining intrinsic error and variations for measured quantity and time-keeping, lists influence quantities, electrical and mechanical requirements, marking requirements and symbols. Concept used and effect of friction between marking device and chart explained in appendices.