Rockwell Automation SF3000 Parallel Gate Amplifier System - Manual (Page 17)

About the PGA Rack 2-1
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About the PGA Rack
The PGA rack provides the mechanical means for mounting the Power Supply module
and the PGA modules. The following sections provide mechanical and electrical
descriptions of the rack.
2.1 PGA Rack Mechanical Description
The PGA rack consists of a sheet metal card-cage type enclosure and a backplane.
The backplane contains a proprietary parallel bus with DIN-style connectors in each
slot for the modules. The leftmost slot is provided for the Power Supply module. The
remaining slots are provided for the PGA modules.
The four-slot version of the rack (see figure 5.1) has three identical 48-pin backplane
connectors: one for the Power Supply module and two for PGA modules. The
eight-slot version (see figure 5.2) has seven identical 48-pin backplane connectors:
one for the Power Supply module and six for PGA modules. The Power Supply
connector in each rack is vertically offset so that the Power Supply and PGA modules
cannot accidentally be interchanged.
The PGA rack must be installed within 18.3 m (60 ft) of the drive’s DC Power Module
to ensure the integrity of the Power Module interface signals. The rack is designed to
be panel-mounted. Mounting holes are provided on the flanges that extend above and
below the rack. A grounding lug is provided on the bottom mounting flange. The rack’s
fan assembly is mounted on the bottom of the rack. Rack installation is described in
chapter 5. Rack specifications are given in Appendix A.
2.2 PGA Rack Electrical Description
The four-slot and eight-slot versions of the rack backplane differ only in the number of
PGA modules they support. The backplane provides power and ground, and two
identical channels ("A" and "B") for gate signals. Six gate signals run on channel A
and six on channel B. Each of the gate signals has an associated common signal. The
connection between the DC Power Technology module and the PGA Power Supply
module determines whether the channel carries the forward or reverse gate signals
(see section 3.2).
The gate signals run to the top portion of each 48 pin connector. Four power and
ground signals, +5V, DCBUS, +5VCOM, and DCCOM, run to the bottom. The power
signals reside on the inside layers of the backplane’s four-layer printed circuit board.
The inner power plane shares both the +5V and DCBUS signals. The inner ground
plane shares the two commons, +5VCOM and DCCOM. A noise filter connects
DCCOM to earth ground.