Central Controllers and Expansion Units Power Supply Units

Fault Indications/ Power supply faults are indicated via relay contacts and LEDs.

Diagnostics

The following table shows when the relay contacts are open or closed:

Power Supply

Switched off

In normal operation

During fault

Relay Contacts 1-2

Open

Closed

Open

Relay Contacts 2-3

Closed

Open

Closed

The LEDs indicate the following faults:

LED

Cause

 

 

ªFan Faultº LED

A fan fault has occurred.

lights up.

 

 

 

ªBatt. lowº LED

The battery voltage has dropped below

lights up.

2.7 V.

 

 

Action

Replace fan

Replace backup battery

System Manual

4-65

C79000-G8576-C199-06

Page 131
Image 131
Siemens S5-135U/155U appendix Diagnostics, LEDs indicate the following faults, Power Supply, Relay Contacts