Proface APL3000B - Node Box PC - Manual (Page 21)

21
• To improve the noise resistance, be sure to
twist the ends of the power cord wires
before connecting them to the Power con-
nector (Plug).
• The PL unit’s power supply cord should
not be bundled with or kept close to main
circuit lines (high voltage, high current), or
input/output signal lines.
• To reduce noise, make the power cord as
short as possible.
• If the supplied voltage exceeds the PL
unit’s range, connect a voltage transformer.
• Between the line and ground, select a
power supply that is low in noise. If there
is an excess amount of noise, connect an
insulating transformer.
• The temperature rating of field installed
conductors: 75
°C only.
• Use constant voltage and insulating
transformers with capacities exceeding
Power Consumption value.
• Connect a surge absorber to handle
power surges.
• Be sure to ground the surge absorber
(E1) separately from the PL unit (E2).
Select a surge absorber that has a
maximum circuit voltage greater than
that of the peak voltage of the power
supply.
3. Grounding Cautions
• Be sure to create an exclusive ground for
the Power Cord’s FG terminal. Use a
grounding resistance of 100
Ω, a wire of
2mm
2
or thicker, or your country’s applica-
ble standard.
• The SG (signal ground) and FG (frame
ground) terminals are connected internally
in the PL unit.
When connecting the SG line to another
device, be sure that the design of the sys-
tem/connection does not produce a short-
ing loop.
• The grounding wire should have a cross
sectional area greater than 2mm
2
. Create
the connection point as close to the PL unit
as possible, and make the wire as short as
possible. When using a long grounding
wire, replace the thin wire with a thicker
wire, and place it in a duct.
4. Input/Output Signal Line Cautions
• All PL Input and Output signal lines must
be separated from all operating circuit
(power) cables.
• If this is not possible, use a shielded cable
and ground the shield.
• To improve noise immunity, it is recom-
mended to attach a ferrite core to the
power cord.
Lightning Surge Absorber
E1 E2
FG
PL
Other
Equipment
Exclusive Grounding
(BEST)
PL unit
Other
Equipment
Common Grounding (OK)
PL unit
Other
Equipment
Common Grounding
(Not OK)
PL unit