Electrical Connection; Emc Protection - HBM PWS Mounting Instructions

Electrical connection

7 Electrical connection
The PWS is a load cell that outputs a mV/V signal based on strain gauges. An
amplifier is needed to condition the signal. All DC amplifiers and carrier-
frequency amplifiers designed for SG measurement systems can be used.
Load cells are executed in a four-wire circuit. Compressive loading produces a
positive output signal.
The cable has different-colored cores, that are assigned as follows:
Input voltage +
Input voltage -
Measurement signal +
Measurement signal -
Sensor cable +
Sensor cable -
Shielding
The connection cable shield is connected to the measuring body.
7.1

EMC protection

Electrical and magnetic fields can often induce interference voltages in the
measuring circuit. Pay attention to the following points to avoid this:
S Use only shielded, low-capacitance measurement cables (HBM measure­
ment cables fulfill this condition) if it is necessary to extend the cable
S Do not route the measurement cable parallel to power lines and control
circuits. If this is not possible, protect the measurement cable with metal
tubing
S Avoid stray fields from transformers, motors and contact switches
S Do not ground transducers, amplifiers and indicators more than once,
S Connect all the devices in the measuring chain to the same protective earth
conductor.
S Always connect the cable shield extensively on the amplifier side, to create
the best possible Faraday cage.
14
= blue
= black
= white
= red
= green
= gray
= yellow,
stranded connection wire insulated over full length
A05750_02_XA0_00 HBM: public
PWS