Siemens S5-135U/155U User Manual
Page 131
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4-65
System Manual
C79000-G8576-C199-06
Power supply faults are indicated via relay contacts and LEDs.
The following table shows when the relay contacts are open or closed:
Power Supply
Relay Contacts 1-2
Relay Contacts 2-3
Switched off
Open
Closed
In normal operation
Closed
Open
During fault
Open
Closed
The LEDs indicate the following faults:
LED
Cause
Action
“Fan Fault” LED
lights up.
A fan fault has occurred.
Replace fan
“Batt. low” LED
lights up.
The battery voltage has dropped below
2.7 V.
Replace backup
battery
Fault Indications/
Diagnostics
Central Controllers and Expansion Units Power Supply Units
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