Rice Lake 920i Installation Manual V1.05 - Manual (Page 10)

6 920i Installation Manual
2.0 Installation
This section describes procedures for connecting load
cell, digital I/O, and serial communications cables to
t h e
9 2 0 i i n d i c a t o r. A s s e m b l y d r a w i n g s a n d
replacement parts lists for the desktop and universal
models are included for the service technician. See
Section 10.11 on page 102 for dimension drawings of
the all models.
• Use a wrist strap to ground yourself and protect
components from electrostatic discharge (ESD)
when working inside the indicator enclosure.
• This unit uses double pole/neutral fusing which
could create an electric shock hazard. Procedures
requiring work inside the indicator must be
performed by qualified service personnel only.
• The supply cord serves as the power disconnect for
the
920i . The power outlet supplying the indicator
must be installed near the unit and be easily
accessible.
2.1 Unpacking and Assembly
Immediately after unpacking, visually inspect the 920i
t o e n s u r e a l l c o m p o n e n t s a r e i n c l u d e d a n d
undamaged. The shipping carton should contain the
indicator, this manual, and a parts kit. If any parts
were damaged in shipment, notify Rice Lake
Weighing Systems and the shipper immediately.
See Section 2.10 on page 12 for parts kit contents.
2.2 Enclosure Disassembly
The indicator enclosure must be opened to install
option cards and to connect cables for installed option
cards.
The 920i has no on/off switch. Before
opening the unit, ensure the power cord
is disconnected from the power outlet.
Ensure power to the indicator is disconnected, then
place the indicator face-down on an antistatic work
mat. Remove the screws that hold the backplate to the
enclosure body, then lift the backplate away from the
enclosure and set it aside.
2.3 Cable Connections
Desktop and universal models of the 920i provide six
cord grips for cabling into the indicator: one for the
power cord, Þve to accommodate cabling for option
cards. Install plugs in all unused cord grips to prevent
moisture from entering the enclosure.
2.3.1 Cable Grounding
Except for the power cord, all cables routed through
the cord grips should be grounded against the
indicator enclosure. Do the following to ground
shielded cables:
¥ Use the lockwashers, clamps, and kep nuts
provided in the parts kit to install grounding
clamps on the enclosure studs adjacent to cord
grips. Install grounding clamps only for cord
grips that will be used; do not tighten nuts.
¥ Route cables through cord grips and grounding
clamps to determine cable lengths required to
reach cable connectors. Mark cables to remove
insulation and shield as described below:
¥ For cables with foil shielding, strip insulation
and foil from the cable half an inch (15 mm)
past the grounding clamp (see Figure 2-1).
Fold the foil shield back on the cable where
the cable passes through the clamp. Ensure
silver (conductive) side of foil is turned
outward for contact with the grounding
clamp.
¥ For cables with braided shielding, strip cable
insulation and braided shield from a point just
past the grounding clamp. Strip another half
inch (15 mm) of insulation only to expose the
braid where the cable passes through the
clamp (see Figure 2-1).
Figure 2-1. Grounding Clamp Attachment for Foil-Shielded
and Braided Cabling
¥ For load cell cables, cut the shield wire just past
the grounding clamp. Shield wire function is
provided by contact between the cable shield
and the grounding clamp.
¥ Route stripped cables through cord grips and
clamps. Ensure shields contact grounding
c l a m p s a s s h ow n i n F i g u r e 2 - 1 . Ti g h t e n
grounding clamp nuts.
¥ Finish installation using cable ties to secure
cables inside of indicator enclosure.
Caution
Warning
Cord grip
Insulated cable
Foil (silver side out) Grounding clamp
Shield wire (cut)
Length of foil before folding
back on cable insulation
Cut insulation here
for foil-shielded cables
Braid
Cut insulation here
for braided cables
NOTE: Install lockwashers
first, against enclosure,
under grounding clamp