User`s guide

Power and Cooling Systems
Table 4–2 (Cont.) Power System Signals
Name Origin Destination Description
BBU Fail Safe Enable
(BBU FSE L)
H405/H7206-B BBU When asserted, the BBU may provide power
to the system. When deasserted, the BBU is
prevented from providing power. The signal
is used during maintenance to prevent the
application of BBU power.
BATTERY BACKUP
REQUEST H (BBUR H)
H7206-B BBU Pulses and is asserted when AC OK deasserts,
thus requesting the BBU to start supplying 300V
DC. BBUA L, BBUE H, and BBU FSE L must
all be asserted for the BBU to respond to the
request pulse.
CHANNEL
n OK (CH n
OK)
Power reg-
ulator n
H7206-B Asserts to tell the H7206-B that the power
regulator specified by the number
n is OK.
OVER TEMPERATURE n H7215 H7206-B Asserts to tell the H7206-B that the H7215
temperature is above specification, causing an
orderly system shutdown followed by a latched
inhibit of the appropriate outputs.
INTERLOCK
n INHIBIT H Cabinet
interlock
switch
H7206-B Asserts to tell the H7206-B that an interlock
switch has been thrown, causing an orderly
system shutdown followed by a latched inhibit of
the appropriate outputs.
BLOWER FAULT H Cooling
system
H7206-B Asserts to indicate that the airflow sensor has
detected a loss of airflow. When asserted
for more than 30 seconds, an orderly system
shutdown occurs followed by a latched inhibit of
the outputs.
CHANNEL
n INHIBIT H7206-B Power reg-
ulator
n
Asserts to command the respective power
regulator to turn off and reset to a ready state
so that output power restores as the signal
deasserts.
SYNC H7206-B Power
regulator
A pulse train used to synchronize dependent
power regulators.
4.1.8 H7236-A Battery Backup Unit
When the system detects a power failure, it signals the H7236-A battery
backup unit (BBU). If the power failure lasts less than one second, the
BBU’s ride-through capability enables the system to function as if nothing
has happened. (Disk drives located in the bottom of the cabinet, however,
are shut down upon detection of the power failure.)
If the power failure lasts longer than one second, Power Fail Interrupt is
signaled and the following actions are initiated:
• The H7236-A supplies full power to the XMI card cage for at least
500 milliseconds while the processors write their cache data back to
memory.
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