Rice Lake 720i Programmable Indicator/Controller - Installation Manual - Manual (Page 12)

6 720i Installation Manual
2.0 Installation
This section describes procedures for connecting load
cell, digital I/O, and serial communications cables to
the
720i indicator. Assembly drawings and replacement
parts lists for the universal model are included for the
service technician. See Section 11.13 on page 111 for
dimension drawings.
CAUTION
• Use a wrist strap to ground yourself and
p r o t e c t c o m p o n e n t s f r o m e l e c t r o s t a t i c
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
720i . 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 720i
to ensure all components are included and 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 2.9 on page 11 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.
WARNING
The 720i 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
The universal model of the 720i provides six cord grips
for cabling into the indicator: one for the power cord,
five to accommodate other cabling. 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 lock washers, 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 (13 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 (13 mm) of insulation only to expose the
braid where the cable passes through the clamp
(see Figure 2-1).
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 backplate,
under grounding clamp
Figure 2-1. Grounding Clamp Attachment for Foil-Shielded
and Braided Cabling