jWlRING 
I 
IGrounding 
I 
Grounding should be done according to the following. 
1. 
Ground the PLC as independently as possible. Class 
3 
grounding should be 
used (grounding resistance 
100 
Q 
or 
less). 
2. 
When  independent grounding 
is 
not  possible,  use  the  joint  grounding 
method as shown below. 
Class 
3 
grounding 
(Best) 
Class 
3 
grounding 
(Goodt) 
Joint grounding 
(Not 
allowed) 
3. 
In the case 
of 
incorrect operation due to grounding, disconnect one or both 
of 
the LG. and FG terminals 
of 
the base units 
from 
the grounding. 
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