Instruction Manual

Adisplayof00 indicates that the enclosure is not connected to the enclosure address bus. When
this condition exists, there is no EMU-to-EMU communication over the enclosure address bus. This
configuration is known as “just-a-bunch-of-disks,” o r a JBOD configuration.
A display of 01 through 14 indicates that the enclosure is physically connected to the enclosure address
bus and can exchange information with other enclosures on the enclosure address bus. The decimal
number indicates the physical p osition of the enclosure in relation to the bottom of the rack.
• 01 is the address of the enclosure connected to the bot tom connector in the first (bottom) junction
box (JB) .
• 14 is the address of the enclosure closest to end of the bus, the top connector in the last (upper) JB.
NOTE:
The enclosure address bus c onnection determines the En. For a single rack, the display is a decimal
number in the range 01 through 14.Foramultiple(two)rackconfiguration, the display is decimal
number in the range 01 thr ough 24.ForJBODconfigurations the enclosure En display is always 00.
You can only display, never change the En value.
Unless there is an error condition, the display automatically returns to the enclosure number (01 through
14 ) one minute after a push-button was last pressed.
Enclosure address bus
The enclosure address bus is composed of cables and either JBs mounted on the rack with screws or shelf
ID expansion cables attached to the rack with velcro straps that interconnect the drive enclosures a nd
controller enclosures to provide a means for m anag i ng and reporting environmental c onditions within the
rack. Two drive enclosures connect with keyed 10-pin connectors to each JB or shelf ID expansion cable.
The EMUs collect the data for the associated enclosure.
The d rive enclosure numbers are always assigned by the enclosure address bus. Connecting the EMU
CAB O NLY connector to either an enclosure ad dress bus JB or shelf ID expansion cable automatically
establishes an enclosure number of 01-14 . Any drive enclosure not connected to the enclosure address
bus has the same enclosure number, 00.
NOTE:
The enclosure number is automatically assigned. You cannot manually assign an enclosure number.
Based on the cable bus installation shown in Figure 38, the enclosures are numbered as shown in
Figure 36.
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Storage system hardware components