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

STSF

Symbols

Station telemetry stale-data flag

Indicates that a measurement or status has exceeded its defined freshness condition. Station automation collects measurements and statuses and issues assigned commands through defined authority paths. A communicated point has a value, quality and equipment identity; it should not be treated as an unexplained contact.

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

A distinction that matters

Stale data must remain distinguishable from a current value. 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

PLC digital input

A PLC digital input reads a documented discrete electrical state from field wiring. The schematic identifies input channel, signal common and field supply as required by the chosen module.

Drawing use: Schematic
Application: Control circuits
Reference family: Manufacturer

A distinction that matters

A digital input reads a state; it does not provide the power output used to drive an actuator.

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.