Seneca SG-EQ4, Руководство по установке

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Grounding and Shielding
Proper grounding and shielding can be criticai to the successful application of load
cells which are generating low level signals (< 5 µV/ scale division). The basic rule is:
A void continuous ground loops; a system should not be grounded at multiple points.
This may occur, tor example, if the shield of the load ce/I cab/e is connected to earth
at both ends.
The great part of load cell cables are provided with a braided shield which provides
protection from electrostatic interference when properly used. This shield is floating
(not connected) at the load cell avoiding the inadvertent creation of a "ground loop".
A basic system configuration is represented in the figure below:
I
1 _ , __ _
i""
- - - ..il
�
1
1
""""'"
................................... ....,
L.C I I
..... - - , - r - --_:_
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1
Junotion · a o
-
x
1
-- , ---r----
r --- · ,
I
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. - - J
The load cell case and junction box are grounded by mechanical attachment to the
structure to which they are mounted. Usually this structure is grounded.
The braided shield enclosing the load cell leads is grounded at the signal conditioning
device/measurer (Z-SG for example), which is grounded through the power cord or
housing
In order to avoid interference, load cells
cables and extension cables should be kept
away from power circuits, with a recommended
distance of at least one meter.
Power supply cables should be crossed at
90
right angles.
loa.d cell l J exte n s. l OJil - ca b
<S J S E I NE C A
ENGLISH - 4/7
MI00155-3-EN