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aTCA-81514PA
5.4 Fan Control
The Fan Tray‘s on
‐
board IPM controller has three operation modes:
Shelf Manager Mode:
The Shelf Manager performs management of the Fan Tray through the two
independent bussed IPMB connections.
Board Control Mode:
The fan tray is controlled by the board in any of the 14 board slots using the
PICMG extended IPMI commands. If the fan tray does not receive the “Set Fan
Level Command” for more than 65 seconds, the fan tray will exit the Board
Control Mode.
Autonomous Mode:
When the connection to the Shelf Manager is lost, or the Shelf Manger is absent, and
the fan tray is not working in Board Control Mode, the fan controller takes over the fan
control after 65 seconds.
Four different control behaviours are user
‐
selectable by a DIP switch located at the
fan tray‘s rear side.
(1)
Full speed
Fan level is set to maximum (15)
(2)
Outlet temperature based control
The fan level depends on the maximum reading of the two NTC sensors above
the card cage and the selected curve.
(3)
Intake temperature based control
The fan level depends on the reading of the LM75 temperature on the fan tray
PCB and the selected curve.
(4)
Fixed speed based control
The fan controller set the fans in a fixed speed.
Figure 11: DIP Switch
