RA8000 and ESA12000 Storage Subsystems
1–20
387404-001
EK–SMCPR–UG. A01
Therefore, both the EMU and PVA monitor all of the power supplies (a maximum of
eight) to ensure that at least four are operational. An error condition is indicated by one of
the following conditions:
•
The +5 Vdc voltage drops to +4.7 Vdc
•
The +12 Vdc voltage drops to 11.4 Vdc
Another voltage essential for proper operation is the +5 Vdc termination power
(TERMPOWER) required for the SCSI bus on each of the six I/O modules. If this voltage
drops to +4.7 Vdc, an error condition exists.
As long as there are four operational supplies and TERMPOWER is correct, the EMU and
PVA generate the POK (power OK) signal. As long as POK is present the array controller
can continue to transfer data providing there are no other error conditions.
The loss of the POK signal for any reason causes the array controller to shut down and
halt all data transfers. All six buses remain quiesced (no data transfers occurring) until the
array controller determines that power is correct. The array controller does this by
checking the status of the POK signal. Until the POK reports that there are at least four
operational power supplies and that TERMPOWER is correct, the array controller, the
cache memories, and all the devices remain passive. The EMU and the PVA continue to
monitor the system and report the error condition.
1.3.3.2 Master Enclosure Controlled Power Shutdown
The EMU can shut down the dc power in the master enclosure or the subsystem when one
of the following conditions occur:
•
The EMU determines an extreme over-temperature condition that requires removing
power from the subsystem
•
The user presses and holds down the PVA dc power switch until the EMU initiates a
controlled power shut down
NOTE
This procedure will only work when the array has been shut
down.
When you initiate a controlled power shut down from the master enclosure PVA the
sequence of events is as follows:
1) The EMU changes its status to indicate that the dc power switch was pressed
2) The master EMU notifies the array controller of the change in status.
3) When the array controller is ready, it sends a controlled power shutdown command
to the master EMU.