Siemens 7SG164 Ohmega 400 Series Manual page 127

2 Trouble Shooting Guide
The following table describes the action of the relay under various conditions, and suggested remedial actions
when problems are encountered.
If problems are being experienced and the suggested action does not work, or the problem is not detailed below,
then please contact Siemens.
SYMPTOM
LCD Screen is faint or difficult to
read.
LCD Screen is dark or has lines
across it.
Protection Healthy LED not lit, LCD
blank, Backlight off & No Flag LEDS
lit.
Relay LCD displays "PSU alarm
asserted, supply out of limits"
Protection Healthy LED blinking,
Messages & cursor blocks flashing
across the LCD screen
Relay displays "Number of inputs or
outputs changed... Relay must cold
start... Settings will be
defaulted...Please press enter"
Protection Healthy LED is flashing.
Protection Healthy Output contact is
not energised.
Protection Healthy LED is steady,
and LCD screen displays ohmega
symbols (Ω).
Protection Healthy Output contact is
not energised.
©2011 Siemens Protection Devices Limited
PROBLEM ACTION
Contrast too low Press TEST/RESET & UP Button
simultaneously
Contrast too high Press TEST/RESET & DOWN Button
simultaneously
Relay is not powered Check Auxiliary DC supply is available.
up Check connections on rear of relay.
Power supply is too Check the magnitude of the input DC
low. voltage. Ensure it is within the relay's
working range of 37.5 to 137.5 V
Internal ribbon cable Check ribbon connection cable to
connection not made. module A is correctly attached.
Internal ribbon Check ribbon connection cables to
connections not made each module are correctly attached.
correctly
Relay has performed If the hardware has not been changed
a cold start due to a (i.e. status input/relay output card
perceived change in added or removed) then there may be a
hardware. problem with the hardware.
Contact Siemens
Watchdog Operated: Contact Siemens
Hardware or
Software Fault
7SG164 Ohmega 400 Series Maintenance
Chapter 10 Page 4 of 6