Siemens Simatic RTU303xC Series Operating Instructions Manual page 47

Information on the tables
LED symbols
The LED symbols in the following tables have the following significance:
Table 2- 3
Symbol
LED status
"Meaning" column
If a cell in the "Meaning" column has several entries with bullets, all or only individual
meanings may apply.
RTU303xC
Operating Instructions, 06/2019, C79000-G8976-C382-06
Meaning of the LED symbols
OFF
LEDs, connectors, buttons, card slots
ON (steady light)
2.2 LEDs
Flashing
47