Side-by-side reference

Understand the difference.

Compare the meaning, drawing context and source references of two entries. A similar graphic or shared abbreviation does not establish equivalence.

First referenceCompare with

SHHA

Symbols

Switchroom humidity high alarm

Reports humidity exceeding the defined supervision condition at the monitored location. Environmental supervision turns measurements or contact states into clearly named room-service indications. A sensor measures a condition; the supervisory function decides whether the assigned alarm or control response is needed.

Drawing use: Schematic
Application: Installation & communications
Reference family: Manufacturer

A distinction that matters

Relative humidity varies with temperature. This reference describes the named application; it does not establish a new IEC graphical symbol, an ANSI device-function number or an exact manufacturer connection diagram.

Full reference

Symbols

Relative humidity sensor

A relative humidity sensor measures moisture in air relative to the saturation condition at the relevant temperature.

Drawing use: Schematic
Application: Metering & protection
Reference family: Manufacturer

A distinction that matters

Relative humidity and absolute water content are different quantities.

Full reference

Follow the full entry for source drawings and the appropriate standard or selected product. Equipment previews show a manufacturer drawing where available, otherwise a 3D thumbnail.