Operating instructions

Operating the LED Display STS2 101
14.1.3 LED Definitions
The following table defines what item that these LEDs monitor:
Table 16 LEDs—Defined
LED Item Monitored Action
IN1A Source 1 input present A green LED is lit if the Source 1
input power is present. This LED
only indicates that power is present
to the power supply; it does not
indicate if the power is within the
programmed tolerances of the unit.
IN2A Source 2 input present A green LED is lit if the Source 2
input power is present. This LED
only indicates that power is present
to the power supply; it does not
indicate if the power is within the
programmed tolerances of the unit
CB1 Circuit Breaker 1 A green LED is lit if CB1 is closed,
indicating power is flowing to the
static transfer switch from Source 1.
CB2 Circuit Breaker 2 A green LED is lit if CB2 is closed,
indicating power is flowing to the
static transfer switch from Source 2.
IN1B Source 1 parameters A green LED is lit if Source 1 power
is within the programmed tolerance
for all phases.
IN2B Source 2 parameters A green LED is lit if Source 2 power
is within the programmed tolerance
for all phases.
STS1 Source 1 SCRs A green LED is lit when the SCRs
for Source 1 are closed.
STS2 Source 2 SCRs A green LED is lit when the SCRs
for Source 2 are closed.
LED_PREF1 Source 1 as the preferred source A green LED is lit if the button has
been pushed to set Source 1 as the
preferred source.
LED_PREF2 Source 2 as the preferred source A green LED is lit if the button has
been pushed to set Source 2 as the
preferred source.
NOXF Transfer inhibited A yellow (amber) LED is lit when
source transfers are inhibited
(locked out) by a hardware
condition. Connect a PC terminal to
the STS2 to locate the exact cause.
See Communication Interfaces
for PC terminal commands.
CB3 Circuit Breaker 3 A green LED is lit if the output
breaker/switch is closed.
CB3A Circuit Breaker 3A A green LED is lit if the output
breaker/switch is closed. CB3A is
installed on units with dual output
breakers.
CB4 Circuit breaker 4 A yellow LED is lit if the Source 1
bypass breaker/switch is closed.
CB5 Circuit breaker 5 A yellow LED is lit if the Source 2
bypass breaker/switch is closed.
OUT Power present to output load A green LED is lit to indicate that
power is present on the output load.