I
NTRODUCTION AND TECHNICAL
D
ATA
The Polyester junction box is designed for the parallel connection of load cells. There are 4 different types:
Type
No. of load cells
Housing size
Inputs
Output
KPF-4
up to 4
100 x 320 x 81 mm
4x M16 or 4x M12
1x M16
KPF-6
up to 6
100 x 320 x 81 mm
6x M16 or 6x M12
1x M16
KPF-8
up to 8
100 x 320 x 81 mm
8x M16 or 8x M12
1x M16
KPF-10
up to 10
100 x 360 x 90 mm
10x M16
1x M16
The junction box type KPF is special designed for weigh bridges and silos including surge arrestors for
lightning protection. It can be connected to the instrumentation with a shielded 6-wire signal cable.
The corner correction is done with resistors. Each junction box already contains 2.1 Ohm resistors for each
load cell from the factory. Therefore it is possible to decrease a load cell signal (use a higher resistance
value) or to increase a load cell signal (use a smaller resistance value).
Housing material:
Polyester
Protection class:
IP66
Cable connection:
With clamping terminals
Corner correction:
By exchangeable resistors
Other: Over-voltage
protection by surge arrestors
M
ECHANICAL
I
NSTALLATION
Look for a mounting location which is more or less dry and protected from environmental stress. The junction
box itself has to be mounted with the cable glands showing vertically to the bottom. A flooding or any tensile
load on the cable glands must be prevented.
All bottom parts of the cable glands are sealed to the housing with some gaskets. You have to check the
existence and the condition of these gaskets, the gaskets have to be replaced if required.
You have to check all bottom parts of the cable glands for a firm seat in the housing.
(Recommendation: use a 12-point ring spanner with a cut-out and metric size 19 mm, if the cable are already
installed).
E
LECTRICAL
C
ONNECTIONS
1
2
2
1
1
2
1
2
2
1
Figure 1: Dimensions in [mm]
The earth screw (see (2) in fig.1) has to be connected to protective earth or you must establish an electrical
connection to the weigh modules for potential equalisation. For doing this only the upper nut should be
loosened and tightened again. The lower nut (= counter nut) and the earth screw with washer must not be
rotated or loosened – the gasket is bonded! If loosened by accident the earth screw must be re-inserted and
locked with some Loctite.
The connection sequence of the load cells should correspond to the corners of the scale, i.e
Corner 1 = Load cell 1, Corner 2 = Load cell 2, etc.
Junction Box Type KPF – Technical Manual, Rev. 1.11 July 2008
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