Chapter 1 - 7SR45 Description of Operation
©2018 Siemens Protection Devices Limited Chapter 1 Page 44 of 48
3.16.5 Sleep Mode
The 7SR45 Argus Relay goes to the sleep mode when the auxiliary power/CT power and USB power are not
available. When the relay is in sleep mode, the user can access the LCD by pressing the BAT ON/OFF key.
In case of inactivity, the relay goes to the sleep mode after 60 s.
When the relay is powered by CT and no auxiliary power and any fault on the system occurs, the relay goes to
sleep mode automatically if the phase CT currents are disconnected.
When the device powered ON through USB power mode and once the USB cable is removed, the device goes to
sleep mode automatically.
NOTE:
During the sleep mode, the 7SR45 Argus Relay has the limited functionality.
3.16.6 Low Battery Status Indication
The low battery LED indication is displayed when the battery voltage falls below the sufficient operating voltage
and an event is generated. In the low battery condition only setting view/edit is allowed.
In the low battery mode, the backlight will not TURN ON.
The low battery can be mapped to a binary output and can be used for remote signalling.
NOTE:
It is recommended to replace the battery when the low battery indication is displayed.
Some of the relay operations such as turning on the backlight and resetting local flag, binary outputs and LEDs in
the low battery mode will lead to insufficient operating voltage. The LCD displays "
INSUFFICIENT ENERGY
"
message and the relay enters sleep mode.
NOTE:
During the low battery, if the battery voltage reduces below 1.5V while doing the setting changes, the device will
enter sleep mode and all unsaved setting changes will be discarded.
NOTE (For selected variants only):
When the battery voltage has dropped below 1.5 V, the low battery LED flickers continuously and indicates that
the critical voltage level is reached. The
Critical Battery
event will be raised.
3.17 Maintenance Mode
3.17.1 Output Test
The output test feature is only visible from the Relay fascia and allows the user to operate the relays functions.
The output test of the selected function will automatically operate the binary Output assigned to that function.
Any protection function which is enabled in the setting menu will appear in the Output Test.
3.18 Self Monitoring
The 7SR45 Argus relay is built in with a number of self-monitoring features. The self monitoring is performed
periodically on boot up. The supervision includes monitoring of power supply signals, code execution watchdog,
memory checks by checksum, RTC check, and battery health checks. The ‘
Protection Healthy
’ LED is
illuminated when the internal power supply signals are healthy.
3.18.1 Internal Relay Failure (IRF)
The internal relay failure feature monitors the healthiness of the relay and supervises the following scenarios in
the presence of auxiliary power/CT power and IRF event will be generated.
1.
Unexpected (Watch Dog) Error
In case of an unexpected behaviour of 7SR45 Argus Relay, IRF condition will be signalled and the relay
restarts.
If this error is observed frequently, the relay should be sent to the factory.
2.
Internal Supply Voltage Error
7SR45 Argus Relay monitors the internal supply voltage and in case of an error, IRF condition will be
signalled.
The protection functions are blocked during this condition.
