Making Ground Connections; Frame And Logic Ground Jumpers - Symmetricom SSU-2000 User Manual

Making Ground Connections

After the SSU-2000 is installed in a suitable rack, connect the shelf to a proper earth
ground.
1. Run a cable from the frame ground (FG) lug to earth ground.
Keep this cable as short as possible. Frame ground connections are made using
two #8-32 studs labeled FG on each side of the lower rear panel. There are also
provisions for making logic ground connections when required by a specific
customers installation. These connections are labeled LG and are located next to
the FG studs and are strapped together with a jumper, as shown in
The jumper strap can be removed to isolate the frame and logic grounds. Logic
ground is AC bypassed to frame ground by capacitor C1 on the backplane.
Note: To isolate frame ground from logic ground, remove the two
jumpers connecting Frame Ground to Logic Ground. Once the
connections to LG have been opened, secure the jumpers to the rear
panel by tightening the FG screws. If desired, either of the LG
terminals may be used to connect a separate Logic Ground cable.
2. Using a digital voltmeter, measure between the ground and chassis and verify
that no voltage exists between them.
Figure 2-2.

Frame and Logic Ground Jumpers

12713020-002-2 Revision D – April 2004
Installing the SSU-2000
Grounding and Power Input
Figure 2-2.
SSU-2000 User's Guide 65