Owner`s manual

5–5Hub Power System
Newly installed half-height network modules receive power immediately. If there is
not sufficient available power for a newly installed half-height network module, then a
full-height module that is currently powered in the lowest slot number will be disabled
so power can be supplied to the newly inserted half-height module.
Newly installed full-height network modules receive power only after the Hub Man-
ager determines how much power is needed and that there is sufficient available
power. If there is not sufficient available power for all full-height network modules
power is allocated from right (slot 8) to left (slot 1).
Installing and Removing Network Modules
It is important to understand how power is allocated by the Hub Manager and what
functions network modules have. All half-height modules power up immediately.
This ensures backwards compatibility with existing DEChub 90 modules.
After a half-height module powers up, the Hub Manager queries the module for its
exact type, and adjusts the power consumption, if necessary. This power will also be
subtracted from the total power available.
Also note that many of the DEChub 90 module labels list the power at the maximum
voltage of 5.1 volts. Refer to each module’s documentation for actual power con-
sumption. In the DEChub 900 MultiSwitch, all 12-volt power is created separately for
each slot from the 15-volt distribution bus. This allows redundancy for the 12-volt
power on a per-slot basis. Power calculations for the 12-volt current assume an
equal current load on the 15-volt supply bus and all 12-volt power is allocated fro the
15-volt power system.
When a half-height module is added to the hub and not enough power is available, a
full-height module with power control may be powered down to provide power for the
half-height module.