HP 748 Series, Руководство пользователя

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Power Budget
Power Budgeting
Power Budgeting
If your workstation’s application requires several accessory cards and mass
storage devices, power budgeting may be required. Power budgeting ensures
that the power needed for the following internal devices does not exceed the
power available:
• Mass storage devices
• Model 743 and Model 744 VMEbus Board Computer(s)
• Standard internal printed circuit boards
• VME, PCI, and EISA accessory cards
The Model 748 ruggedized workstation uses two power supplies. Each
power supply provides voltages to the workstation's modules and accessory
card slots as listed in Table 2-6 and Table 2-7.
These tables are also worksheets to use in determining your power budget.
You may photocopy these tables as needed.
To determine the workstation’s power needs, follow these instructions:
1 Determine the board computer’s current requirements from the Computer
Current Requirements Worksheet (Table 2-3 or Table 2-4).
2 To determine the maximum current usage of the Model 744 memory
cards, either use Figure 2-1 and Table 2-1 (for Model 744/132L) or Table
2-2 (for Model 744/165L). You must work with the worst case power
draw to correctly determine power usage. Determine worst case power
draw by examining active memory bank configurations, using the follow-
ing steps:
a Examine your memory card configuration, noting which size card is in
each memory slot.
b The worst case active memory bank configuration depends on the slot position of the
memory cards, and the size of the cards. The 32 MB memory card has two banks per
card, and the 16, 64,128, and 256 MB cards each have only one memory bank per card.
• When 32 MB cards are used as a pair in memory slots 2 and 3 they can use three
memory banks concurrently.
• When used as a pair in slots 0, 1, or 2, the 32 MB cards can have two active mem-