HP Array Controller HSG V8.7 Software - Manual (Page 92)

Power Verification and Addressing
4–6 UltraSCSI RAID Enclosure
Monitoring Power Supply Operations
Even with four operational power supplies, it is possible that a power
supply problem might cause one or both of the dc voltages to be too
low. Both the PVA and the EMU monitor power supply operations to
ensure that the dc voltages are within the ranges specified in Table
4–1.
With at least four operational power supplies, the minimum voltage
levels sufficient to run the system are present. Fewer than four
operational power supplies cannot maintain the minimum voltages. If
this occurs, the EMU notifies the array controllers so they can shut
down before standby power mode is initiated.
Caution
Some array controllers bypass the standby power mode
functionality from the PVA standby power switch. Refer to
the array controller documentation for availability of this
feature.
Note
The EMU monitors the system dc voltages and I/O module
+5 V dc TERMPOWER. The PVA only monitors the
system dc voltages.
Table 4–1 DC Voltage Ranges
Nominal Voltage +5 V dc +12 V dc
Minimum Voltage +4.7 V dc +11.4 V dc