Fault Indications/Diagnostics; Fault Indications/ Diagnostics - Siemens S5-155U System Manual

Fault indications/
diagnostics
System Manual
C79000-B8576-C199-03
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
Switched off Open
In normal operation Closed
During fault Open
The LEDs indicate the following faults:
LED Cause
"Fan Fault" LED A fan fault has occurred.
lights up.
"Batt. low" LED The battery voltage has
lights up. dropped below 2.7 V.
6ES5 955-3NA12 Power Supply Unit
Relay Contacts 2-3
Closed
Open
Closed
Action
Replace fan
Replace
backup
battery
4
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