Specifications

Introduction
31004624 8/2009 11
Integrated Power Supply
The NIM’s built-in 24-to-5 VDC power supply provides logic power to the I/O
modules on the primary segment of the island bus. The power supply requires a
24 VDC external power source. It converts the 24 VDC to 5 V of logic power for the
island. Individual STB I/O modules in an island segment generally draw a logic bus
current of between 50 and 265 mA. (Consult the Advantys STB System Planning
and Installation Guide for current limitations at various operating temperatures.) If
the logic bus current drawn by the I/O modules totals more than 1.2 A, additional
STB power supplies need to be installed to support the load.
The NIM delivers the logic power signal to the primary segment only. Special
STB XBE 1300 beginning-of-segment (BOS) modules, located in the first slot of
each extension segment, have their own built-in power supplies, which provide logic
power to the STB I/O modules in the extension segments. Each BOS module that
you install requires 24 VDC from an external power supply.