ISA-82.03:1988

This standard applies to electrical, electronic (analog/digital) and electromechanical process measurement and control equipment which
measures and controls directly or indirectly an industrial process through a final control element (or elements);
is intended to be connected to supply circuits which do not exceed 250 volts rms, single phase, or dc; and
is rated for use in either indoor, outdoor or sheltered locations.
This equipment includes but is not necessarily restricted to
indicating, integrating or recording equipment with or without a control function;
transmitters;
transducers;
analyzers;
supervisory or telemetry equipment; and
accessories used with any of the above equipment.