User guide

Installation 17
3.5 Grounding the Chassis
The backplane’s mounting holes may be grounded in two ways.
First, the mounting holes labeled as GND with circle soldering
mask can be connected to the signal ground plane of the back-
plane. Second, the mounting holes labeled as FGND with square
soldering mask can be connected to the power ground plane (the
earth), and is isolated from the signal ground.
A proper signal and power wiring helps reduce the effects of
ground loop and increases the accuracy of measurement.
By default, the PXIS-3320 backplane is mounted on the chassis
through the FGND mounting holes. The signal ground (GND),
therefore, is isolated to the power ground (FGND). For applica-
tions that require the short of signal ground and power ground, an
external wiring is needed to connect the GND and FGND solder-
ing pots.
3.6 Changing the Power Supply Modules
The PXIS-3320 chassis comes with two 3U CompactPCI power
supply modules, while the PXIS-3320/1000W chassis comes with
four 3U CompactPCI power supply modules. The power supply
modules are current-sharing and are hot-swappable.
To replace the power modules:
1. Release the handle of the defective power module.
2. Push down the handle to eject the power module from
the chassis.
3. Carefully pull the power module out from the chassis,
then set aside.
4. Align the top and bottom edges of power supply modules
to the card guides, then install the power supply module
into the chassis.
5. Use the handle to firmly connect the power module into
the chassis backplane.