Ransburg 9060 LV Auto Cascade 80120-XXX - Manual (Page 23)

9060 Cascade Low Voltage Controller - Installation
CP-13-02.2 18
ELECTRICAL NOISE
Electrical noise refers to stray electrical signals
in the atmosphere at various signal strengths
and frequencies that can affect the operation of
equipment. One of the best ways to prevent
this is to shield the equipment and cables within
a continuous ground envelope, such that any
incident noise will be conducted to earth ground
before it can affect the circuit conductors.
For conductors inside the control unit or Con-
troller, the grounded enclosures provide this
envelope. For the cables that connect the
applicator to the control unit or Controller, a
shielded cable has been used. The shield
consists of an overall foil shield in combination
with an overall braided shield. This provides
the most effective shielding, as the foil covers
the “holes” in the braid, and the braid allows for
practical 360° termination at both ends of the
cable.
The AC input cord is not shielded, but is di-
rected to an AC line filter as soon as it enters
the cabinet. This method filters out most of the
noise that comes in on the AC line. For maxi-
mum noise immunity, if the AC line is wired
using conduit instead of the provided AC line
cord, it should connect to the filter as soon as it
enters the cabinet with as short of leads as
possible. Additional noise protection can be
provided by running the AC input line to the
control panel in grounded conduit.
For maximum noise protection any user supply
input/output (I/O) wiring should be made using
shielded cable (or conduit) which is connected
to earth ground in a continuous 360° fashion at
both ends. The best way to do this is to use a
connector (conduit fitting) at each end of the
cable (conduit) that makes contact to the shield
(conduit) in a full 360° circle around the cable
(conduit) and makes contact to the grounded
enclosure in the same fashion. Connecting the
drain wire of a shield to a ground point on or in
the cabinet (usually referred to as pigtailing) is
not an effective method of shielding and actual-
ly makes things worse (see Figure 5).
Figure 5: Pigtailing Connection
It is recommended that all AC I/O (interlocks)
be run in conduit. If desired and codes permit,
cabling may be used for these signals, but for
maximum noise immunity the cabling must
contain overall foil and braided shields and be
terminated as described in the preceding
paragraph.
Cable is recommended for all of the analog and
digital remote I/O control signals including the
relay controlled DC I/O (high voltage output
signal, fault output signal). Again, for maximum
noise immunity the cabling must contain overall
foil and braided shields and be terminated in a
continuous 360° manner as described in the
preceding paragraph. Special fittings have
been provided on the control panel for termina-
tion of these cables at that point. The use of
these fittings is described in the corresponding
sections of this manual.
Using the methods previously described, the
9060 Controller have been successfully tested
to the stringent standards of the Electromagnet-
ic Compatibility Directive of the European
Union. The results conclude that these units
are neither a source of electrical noise nor