SCSI Backplane Board | Intel® Server Platform SR6850HW4 TPS |
7.2.2.3Over-current Protection (OCP)If either power rail for a drive exceeds 6A on 12V or 4.5A on 5V, the MOSFET switch for the out-of-spec rail is turned off. Removing power protects the MOSFET and the platform from damage if a short occurs on one of the power rails. After one-third of a second, the MOSFET is turned on to see if the short has been removed. It will continue turning on and checking for a short every one-third of a second until the system instructs the SCSI Backplane Board to remove power or until the fault disappears.
When the MOSFET is first enabled, the over current condition is not detected during the power- up period. This no-OCP period allows the initial current surge produced by many hot-swap SCSI hard disk drives. The power-up period is short enough to prevent damage to occur to the MOSFETS or the platform.
7.2.2.4Power Control InterlockThe power control interlock prevents drives from powering on at the same time. Since only one hot-swap SCSI hard disk drive can power on at once, the board power requirements can be kept lower. Drives power on at one-third second intervals.
7.2.2.5System Status NotificationHot-swap SCSI hard disk drive status information is collected by the Qlogic* GEM359 SAF-TE controller for each bus. The controller passes the information to the server management via the global I2C bus and enclosure management information via the SCSI bus.
7.2.2.6SCSI Status LEDsThe status LEDs give the user a visual indication of the status of each hot-swap SCSI hard disk drive. A single bi-color (amber and green) LED is present for each drive. The LEDs use a combination of color and blinking frequency to indicate multiple conditions.
The hot-swap SCSI hard disk drive status LEDs are located on the SCSI Backplane Board and projected out the front system by light pipes on the drive carrier. The states of the LEDs are described in Table 39.
Table 39. Hot-swap SCSI Hard Disk Drive LED Details
LED State | Description |
Green on | Drive is being initialized |
| |
Green blinking | Drive is active |
| |
Amber on | Drive/slot failure |
| |
Amber slow blinking (~1Hz) | Predictive drive/slot failure or array rebuild is in process |
| |
Amber fast blinking (~2.5Hz) | Array rebuild interrupted, rebuild on empty slot, or identify slot |
| |
74 | Revision 1.0 |
| Intel order number D23151-001 |
