44
(d) When the main circuit line and power line cannot be
separated, use a shielding cable and ground it on the
programmable controller side.
However, ground it on the opposite side in some cases.
(e) When cables are run through pipes, securely ground the
pipes.
(f) Run the 24VDC input line away from the 100VAC and 200
VAC lines.
(g) The cabling of 200m (656.2ft.) or longer distance may produce
leakage current depending on the capacity between lines and
result in an accident.
(h) As a countermeasure against the power surge due to lightning,
separate the AC wiring and DC wiring and connect a surge
absorber for lightning as shown in (i) of item (1).
Failure to do so increases the risk of I/O device failure due to
lightning.
(3) Grounding
(a) Carry out the independent grounding if possible. (Grounding
resistance 100Ω or less.)
(b) If the independent grounding is impossible, carry out the
shared grounding (2) as shown below.
(c) Use the cable of 2mm
2
or more for grounding.
Set the grounding point closer to the programmable controller
to make the grounding cable short as possible.
(d) If a malfunction occurs due to earthling, separate either LG or
FG of the base module, the device combination, or all the
connection from the earthling.
RA
Shield jacket
Shielded cable
DC
Output
Input
Programmable controller
controller
Programmable
controller
Programmable
grounding
Class 3
device
Other
device
Other
(3) Common grounding.....Not allowed(2) Shared grounding.....Good(1) Independent grounding.....Best
grounding
Class 3
device
Other
controller
Programmable
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