User's Manual

Electrical connection
36 A4429-1.0 HBM: public T40FH
Special electronic coding methods are used to protect the
purely digital signal transmission between the transmitter
head and the rotor from electromagnetic interference.
The cable shield is connected with the transducer hous
ing. This encloses the measurement system (without the
rotor) in a Faraday cage when the shield is laid flat at
both ends of the cable. With other connection techniques,
an EMC-proof shield should be applied in the wire area
and this shielding should also be laid flat (also see HBM
Greenline Information, brochure i1577).
Electrical and magnetic fields often induce interference
voltages in the measuring circuit. Therefore:
S Use shielded, low-capacitance measurement cables
only (HBM cables fulfill both conditions).
S Only use plugs that meet EMC guidelines.
S Do not route the measurement cables parallel to
power lines and control circuits. If this is not possible,
protect the measurement cable witha steel conduit,
for example.
S Avoid stray fields from transformers, motors and con
tact switches.
S Do not ground the transducer, amplifier and indicator
more than once.
S Connect all the devices in the measuring chain to the
same protective conductor.
S In the case of interference due to potential differences
(compensating currents), supply voltage zero and
housing ground must be disconnected on the amplifier
and a potential equalization line established between
the stator housing and the amplifier housing (copper
conductor, minimum 10 mm
2
wire crosssection).