Electrical Connection; Notes On Cabling; Assignment Of Cable Wires - HBM U93 Notice De Montage

U93
6

Electrical connection

The transducers are delivered with a 3 m cable with free ends as standard,
and the cable terminations are color‐coded. The cable shield is connected in
accordance with the Greenline concept. This encloses the measurement sys­
tem in a Faraday cage. Electromagnetic interference cannot affect the mea­
surement system.
Transducers with free ends must be fitted with CE‐norm connectors. The
shielding must be connected extensively.
With other connection techniques, an EMC‐proof shield should be applied in
the wire area and this shield should also be connected extensively (see also
HBM Greenline Information, brochure i1577).

6.1 Notes on cabling

• Use shielded, low‐capacitance HBM cables only.
• Do not route the measurement cables parallel to power lines or control
circuits. If this is not possible (in cable pits, for example), protect the
measurement cable with a rigid steel conduit, for example and keep it at
least 50 cms away from the other cables. The power lines or control circuits
should be twisted (15 twists per meter).
• Avoid stray fields from transformers, motors and contact switches.
• Do not ground the transducer, amplifier and indicator more than once, and
attach all the devices in the measuring chain to the same protective earth
conductor.
• The connection cable shielding is connected to the transducer housing.
• Follow the connection diagram and keep to the (Greenline) grounding
concept.
• To achieve full accuracy, a six‐wire configuration should be used for an
extension cable.

6.2 Assignment of cable wires

If the transducer is connected in accordance with the wiring diagram below
(Fig. 6.1), when the transducer is loaded in the pressure direction, the output
voltage at the amplifier is positive.
A2081-2.2 en/de/fr
15
HBM