Rackable Systems OmniStor 4700S Series, User Manual

Page: 24 / 108

Chapter 1 - Getting Started
Automatic Termination Override
12
In a Expansion Connection configuration (daisy-chain), enclosures are cabled to each other
up to a maximum of three (3) enclosures. Since the RAID Controller is not supplying the
term power, a manual override is provided through the switches. This is due to a logical
condition where termination is disabled when a cable is sensed plugged into the connector.
The controller relies on the host HBA to supply the term power. When connecting this
configuration you will be instructed to set the switch settings to the Up positio on the
enclosure’s RAID Controller for those enclosures between the host and the last enclosure
in the daisy-chain. The switches on the last enclosure should be set to the down position.
Their default position is the down position.
Daisy-Chain Enclosure Termination Switch Settings
1 2 3 4
ON
1 2 3 4
ON
1 2 3 4
ON
RS-232
DTE
H OST CH 1 H OST CH 0
H OST CH 1 H OST CH 0 DR
T H1A
BK1A
PWR H0A BK0A
RS-232
DTE
H OST CH 1 H OST CH 0
H OST CH 1 H OST CH 0 DR
T H1A
BK1A
PWR H0A BK0A
RS-232
DTE
H OST CH 1 H OST CH 0
H
OST
CH
1
H
OST
CH
0
DR
T H1A
BK1A
PWR H0A BK0A
SCSI Data Cable
SCSI Data Cable
SCSI Data Cable
SCSI Data Cable
SCSI Data Cable
SCSI Data Cable
Host Server
Host Server
HBA (Initiator ID 7)
HBA (Initiator ID 7)
Set Switches 1 - 4
to the up position
Set Switches 1 - 4
to down position
Upper Channel 1
Lower Channel 1
Upper Channel 0
Lower Channel 0