Intel® Server System Server System "Emerald Ridge ... - CTL

錯 誤 ! 尚 未 定 義 樣 式 。 EPSFunctional Specification3.28.3 Power Supply Fan Speed ControlA component of Emerald Ridge thermal management is BMC control of power supply fan speed.All control of power supply fans by the BMC is done via PMBus commands. Controlling of PSFan happens through setting PWM value. The fan control OEM SDRs used for power supplycontrol will therefore specify the control data as PWM values. In order for the fan speed controllogic to work correctly, the SDRs must be reloaded any time the power supply configuration ischanged in order to load the proper SDRs for the given power supplies.Power supplies have internal fans which provide cooling to the power supplies and to the harddisks. The power supply fan speed control is influenced by the power supply internal logic alongwith system level control. The power supply fans operate from distributed 12V power. If a powersupply is installed, the power supply fans will always have 12V power applied and allow fullPMBUS control, even if the power supply is failed.The following factors will influence the power supply fan speed.1) Internal control. Internal control is based on an internal temperature sensor along withpower supply load. These details are documented in the power supply specification.2) Front Panel Thermal Sensor Clipping curves. The front panel sensor must bemapped via the piecewise upper and lower clipping curves to the power supply fans.3) Lookup Table. In order to sufficiently cool the hard disks, the power supply fans speedmust also react to the main system fans speeds. Since the main system fans are in fourfan zones, the maximum aggregate system fan speed will be used in the lookup table.The following table shows an example of the lookup table. The specific values in thelookup table will be based on system testing. The table should be flexible and allowvalues to be changed through an SDR mechanism. There must be a unique lookup tablefor each power supply configuration. This results in four lookup tables, one for eachpower supply configuration. The lookup table will specify a power supply PWM value.Revision 1.1Intel ® Confidential 47