Electrical Connection; Notes On Cabling; Assignment Of Cable Wires - HBM HBK U93 Mounting Instructions

7

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 system in a Faraday cage. Electro­
magnetic interference cannot affect the measurement 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 Informa­
tion, brochure i1577).
7.1

Notes on cabling

S
Use shielded, low‐capacitance HBM cables only.
S
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).
S
Avoid stray fields from transformers, motors and contact switches.
S
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.
S
The connection cable shielding is connected to the transducer housing.
S
Follow the connection diagram and keep to the (Greenline) grounding concept.
S
To achieve full accuracy, a six‐wire configuration should be used for an extension
cable.
7.2

Assignment of cable wires

If the transducer is connected in accordance with the wiring diagram below (Fig. 7.1),
when the transducer is loaded in the pressure direction, the output voltage at the ampli­
fier is positive.
14
MECHANICAL INSTALLATION
U93