RFL 9300 RFL Electronics Inc.
October 29, 2001 10 - 9 (973) 334-3100
89B (U1-6)
This signal is received from the Alarm I/O module (Section 21). It reflects the status of a disconnect
switch at the local station. It is a logic low whenever the disconnect switch is opened, and a logic high
when it is closed. When the supervisor detects an opened disconnect switch, the relay is placed in stub-
bus active mode. See paragraph 3.13.
DTT TX (U1-8)
This signal is also received from the Alarm I/O module. It reflects the status of the Direct Transfer Trip
signal at the local station. A logic zero indicates an active DTT signal. The Supervisor Controller sends
this signal to the remote RFL 9300 through the Communications Controller.
RECLOSE (U1-7)
This is an active-low logic signal sent to the Alarm I/O module. It is generated by the Supervisor Con-
troller whenever a three-phase trip is detected. It causes a reclose block signal to be generated on the
Alarm I/O module. This is designed to prevent the main breaker at the local station from reclosing into a
three-phase fault. This signal is disabled if the watchdog timer expires.
LOCAL ALARM RELAY (U1-3)
COMM ALARM RELAY (U1-5)
These are alarm signals generated by the Supervisor Controller. They control the electromechanical
System and Communications Alarm relays on the Alarm I/O module. These normally-open relays are
de-energized when an alarm condition is detected, so a logic one output signifies the alarm condition.
These signals are disabled if the watchdog timer expires. This will de-energize both relays and cause
alarms to be issued.
SPARE (U9-27)
This input signal line has no function at this time.
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