Rice Lake Survivor RT, Руководство пользователя и инструкция по установке

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6
Survivor
®
RT
Installation Manual
3.0 Junction Box and Grounding
Cable installation instructions for the weigh module(s) are included in the following paragraphs:
3.1 Load Cells to Junction Box
Each load cell is equipped with 30' of load cell cable,
sufficient to reach a centrally-located junction box on
standard scales. A conduit adapter and a 14" section of
3/4" flexible conduit is supplied for both ends of each
load cell cable located at the load cell and at the
junction box. Main conduit runs between these 14"
flexible end sections are 3/4" galvanized metal
conduit already installed on the deck as shown above.
NOTES:
• Flexible conduit can not come in contact with the
ground. Plastic tiewra ps are inc luded in the
hardware shipping box and should be used to tie up
the flexible conduit.
• If using a single B module, some of the conduit runs
are not used. These conduit runs are used when
more than one B modules are installed.
3.2 Junction Box to Indicator
Fifty eight (58) feet of six-wire homerun cable is
supplied for wiring the junction box to the indicator. It
is run in 3/4" galvanized metal conduit from the
junction box to the indicator. Conduit for this purpose
is to be obtained locally. A 30" flexible conduit
section and conduit connector is provided where this
cable exits the junction box. Do not run any other
electrical cables in or near the conduit to the indicator.
3.3 Indicator to Peripherals
All 3/4" conduit for cabling from the indicator to
remote displays and other peripheral devices is to be
obtained locally. Conduit runs may be buried in a
trench or secured above ground. Use separate conduit
runs for AC power and DC data lines to avoid
interference. As a general guideline, run AC and DC
cables in separate trenches if possible. When DC data
cables must run in the same trench as AC power lines,
separate cables as much as possible (preferably more
than 34" apart).
3.4 Single-Point Ground Conductor
A bare 10 gauge solid wire is to be run from the scale
frame to the grounding lug on the junction box then
underground to the main AC power earth ground. If
the DC transient protection board is installed, the
ground conductor should also be connected to the
transient protection board’s ground lug.
3.5 Junction Box Connections
Each junction box is large enough to hold the
summing board, transient protection devices,
packaged desiccant, and extra load cell cable coiled
inside the enclosure. An industrial corrosion inhibitor
and desiccant such as the RLWS Industrial Corrosion
Inhibitor (PN 16037) should be added to the junction
box enclosure before final closure.
IA summing card mounted within the junction box is
used to make all cable terminal connections. All
terminal pins are clearly marked as to function.
3.6 Electrical Ground Connections
Improper grounding systems are often a
cause of corrupted data from ground-loop
current flows and costly lightning damage
to electronics.
Always strive for a single-point grounding system.
Do not drive ground rods at the scale location which
establishes separate earth grounds for the scale. These
separate earth grounds will not share the same zero
reference as the existing earth ground for the AC
power system. This difference in electrical potential
invites ground-loop current flow between the separate
grounds, often corrupting serial data like RS-232
which depends on a stable zero reference.
In addition, a separate earth ground system at the scale
can actually invite lightning or power surge damage:
• A minor powerline surge should immediately
be shunted to ground. If a separate ground
system exists at the scale with a lower
potential than the main ground, the surge may
travel out to the scale ground rod, damaging
load cells on its way.
• A nearby lightning ground strike may
instantly raise the zero potential of a ground
rod at the scale location, while leaving the
scale house ground rod unaffected. That
lightning surge will now take the easiest path
to the lower-potential ground—through the
scale wiring and back to the scale house
ground, possibly damaging the indicator on
its way.