Rockwell Automation 1771-A1B_A2B_A3B_A3B1_A4B SERIES B Universal I/O Chassis Installation Instructions - Manual (Page 8)

Universal I/O Chassis 8
Publication 1771ĆIN075A-EN-P - March 2002
If you have this I/O chassis Type of mount
1771ĆA1B, ĆA2B, ĆA3B1, ĆA4B panel mount (rear mount)
1771ĆA3B 19" rack mount (front mount) or panel mount (rear mount)
Each enclosure must contain a central ground bus. The ground bus
is the common connection for each chassis within the enclosure and
the enclosure itself. Use either bolts or welded studs to mount the
I/O chassis and central ground bus. If you are mounting a chassis to
the back panel of an enclosure, use 1/4-20 (M6 x 10) mounting bolts.
Mounting Bracket
or Ground Bus
Flat
Washer
Flat
Washer
Stud mounting of a ground bus or chassis to the back panel
Scrape paint
Welded Stud
Back Panel
If the mounting bracket is coated
with a non-condutive material
(anodized, painted, etc.), scrape
the material around the mounting
hole.
Star
Washer
Nut
Nut
Back Panel
Back Wall of
Enclosure
Welded
Stud
Scrape paint on panel and
use a star washer.
Stud mounting of the back panel to the enclosure back wall
Use a wire brush to remove
paint from threads to allow a
ground connection.
Ground Bus or
Mounting Bracket
Flat
Washer
Flat
Washer
Scrape paint on
panel and use
star washers.
If the mounting bracket is
coated with a non-conductive
material (anodized, painted,
etc.), scrape the material
around the mounting hole.
Star
Washer
Nut
Bolt mounting of a ground bus or chassis to the back panel
Bolt
Back Panel
Tapped
Hole
Back Panel
Bolt
If the mounting bracket is coated with
a non-conductive material (anodized,
painted, etc.), scrape the material
around the mounting hole.
Scrape Paint
Flat
Washer
Flat
Washer
Star
Washer
Tapped Hole
Mounting Bracket
Alternative bolt mounting of chassis to the back panel
17666 17664
17665 12342-I
ATTENTION
!
If the mounting brackets of a chassis do not lay
flat before the nuts are tightened, use additional
washers as shims so that the chassis will not be
warped by tightening the nuts. Warping a
chassis could damage the backplane and cause
poor connections.
For further information, refer to publication 1770–4.1, “Industrial
Automation Wiring and Grounding Guidelines.”
Mount the I/O Chassis
and Ground Bus