Siemens SIMATIC S7 - LED Indicators

2-3
SM 338 Equipment Manual
(4) J31069-D401-U1-A0-7618
The LED indicators on the front of the module have the functions listed in
table 2-1.
Table 2-1 LED indicators
Indicator
Function
DC (green)
External voltage present
External voltage not present
SF (red)
System error/module requires diagnosis
Normal operation
LED indicators
The SM
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Modu
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