Chapter 1. Product Description
EK–SMCPP–UG. A01
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1.3.2 Environmental Monitor Unit (EMU)
The primary function of the EMU (see Figure 1-9) is to monitor, process, report,
and display enclosure and controller environmental status information for the
power supplies, temperature, blowers, configuration, SCSI addressing, I/O
modules, communications, and the EMU microcode type. The EMU and
controller can exchange and process this information.
CAUTION
Proper operation of an UltraSCSI subsystem
requires an operational EMU and PVA in each
BA370 rack mountable enclosure. You must also
establish communications links between the
EMUs to ensure proper subsystem operation and
error reporting.
The primary EMU function is monitoring and reporting UltraSCSI enclosure
environmental status. In conjunction with the PVA and the controller, the EMU
identifies controller faults and alerts the user of existing or impending failures
using one or more of the following error reporting systems:
•
EMU LEDs
•
The EMU audible alarm
•
Error messages on the host interface
•
Enclosure system OK LED
•
Enclosure system fault LED
In some instances, such as blower failures or high ambient or internal enclosure
temperatures, the EMU automatically initiates corrective actions (for example,
operating the blowers at high speed).
When there is the possibility of component damage due to overheating, the EMU
can initiate an automatic controlled power shut down.
1.3.2.1 Controller Status
The master EMU also monitors the state of both controllers. Should the EMU
detect a controller fault it can:
•
Sound the audible alarm
•
Cause the EMU system fault status LED to flash
•
Display a controller fault code on the blower LEDs when you momentarily
press the Alarm Control switch
