Measurement Computing STLITE-CPCI-xxx - Manual (Page 6)

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2. COMPONENTS – STANDARD SYSTEM
The STLITE-CPCI-16R (Figure 2-1) consists of the following major components:
Figure 2-1. STLITE-CPCI-16R
2.1 CPCI EXPANSION MOTHERBOARD
The expansion motherboard is a printed circuit board mounted vertically in the back of the rack enclosure. It
receives bus signals from the host computer and places equivalent signals on the chassis secondary buses. There
are either eight or sixteen slots on the secondary bus for installing boards. Each group of eight slots is serviced
by an Intel 21150-AC, 32-bit, 33 MHz bridge chip.
A semiconductor sensor is provided on the expansion motherboard for temperature monitoring. Its output is
applied to an A/D converter along with power supply voltages (±12V, +5V, and +3V). If the optional fan tray is
used, two voltage signals from two pairs of DC-powered cooling fan are applied to the A/D for conversion.
Optionally, each of the eight (or sixteen) card slot locations has a semiconductor temperature sensor mounted
over it. The sensors are mounted on a PCB strip mounted on the top of the chassis. Signals from these sensors
are converted to digital values by a second A/D. The digital values, along with other monitor data, are sent to the
host computer over the expansion cable.
2.2 HOST BRIDGE CARD: STLITE-PCI-HOST; STLITE-CPCI-HOST
The Host Bridge card is a PCI or CPCI adapter card that can be installed in any open slot in the host computer.
The Host Bridge card is connected via a three-foot shielded ribbon cable to an expansion bridge card in the back
of the STLITE-CPCI-8R/16R Expansion Chassis.
2.3 POWER SUPPLY
The STLITE-CPCI-8R/16R incorporates a standard 250-Watt, ATX-type switching power supply in the cabinet.
A cooling fan is integrated in the power supply. All four output voltages are monitored to an accuracy of ±2%.
The power supply operates on either 115 or 230VAC (switch-selected).