Connecting Several Weighing Modules In Parallel; Connection Using Four-Wire Circuitry; Cable Extensions - HBM Z6AM Montageanleitung

Z6AM
Electrical and magnetic fields often induce interference voltages in the mea-
surement circuit. Therefore:
− use shielded, low-capacitance measurement cables only (HBM cables ful-
fill both conditions)
− do not route the measurement cables parallel to power lines and control
circuits. If this is not possible, protect the measurement cable with steel
conduit for example
− avoid stray fields from transformers, motors and contact switches

6.1 Connecting several weighing modules in parallel

Load cells can be wired in parallel by joining the load cell cable core ends of the
same color. In this case the HBM range offers terminal boxes of the VKK... series.
The output signal is then the average of the individual output signals.
CAUTION
Overloading of an individual load cell cannot then be detected from the output
signal.

6.2 Connection using four-wire circuitry

In the event of connections to amplifiers using four-wire circuitry, the cores bl
(blue) and gn (green) should be connected together, as should bk (black) and
gr (gray). The following deviations occur in the case of cable of original length
(3 m): Sensitivity −0.2 % and temperature coefficient −0.01 %/10 K.

6.3 Cable extensions

Extension cables must be shielded and of low capacitance. We recommend
the use of HBM cables, which satisfy these requirements.
With cable extensions it is important to ensure that a good connection is pro-
vided, with minimum contact resistance and good insulation.
When using six-wire circuitry, the effects of resistance changes in the exten-
sion cable are compensated. If you extend the cable using four-wire circuitry,
the sensitivity deviation can be rectified by adjusting the amplifier. However,
temperature effects are only be compensated when operating with six-wire cir-
cuitry.
Route the load-cell connection cable so that any condensed water or damp-
ness forming on the cable can drip off. It must not be able to reach the load
cell. In addition ensure that no dampness can penetrate the open ends of the
cable.
A1559-2.0 de/en/fr
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HBM