VEGA VEGASCAN 850 - Manual (Page 53)

VEGASCAN 850 53
Electrical connection
5 Electrical connection
5.1 Connection, connection cable
and shielding
Qualified personnel
Instruments which are not operated with
protective low voltage or DC voltage must
only be connected by qualified personnel.
This is especially valid for the connection of
the power supply on VEGASCAN.
Safety information
As a rule, do the work in the complete ab-
sence of voltage. Always switch off the power
supply before you carry out connecting
work. Protect yourself and the instruments.
The shielded transducer cables transmit a
signal with a voltage of approx. 1 kV. In Ex
areas, cable damage can be dangerous. Do
not carry out any mounting or connection
work on the transducer when VEGASCAN is
switched on.
Connection cable
Please note that the connection cables are
specified for the expected operating tempera-
tures in your systems. The power supply and
the sensor cables must have an outer diam-
eter of 6 … 12 mm, to ensure the seal effect of
the cable entry.
Power supply
For power supply, standard three-wire cable
up to max. 2.5 mm
2 can be used. The electri-
cal connection is made via spring terminals.
You open the terminal opening with a small
screwdriver by inserting it into the opening
slot above the terminal position and lever it
upward. This opens the terminal and the
copper core of the connection wire can be
inserted.
Transducer cable
When wiring the transducer cable (version C
and D), strong bending of the cable should
be avoided. This is a special cable which can
be damaged.
Make sure when wiring the transducer cable
that no operating influences can damage it.
Earth conductor terminal
The electronics housing of the sensors has a
protective insulation. The earth conductor
terminal and the earth terminal in the electron-
ics housing are galvanically connected with
the metallic transducer diaphragm.
On sensors in version B, the earth conductor
terminal is galvanically connected to the
transducer diaphragm via the transducer
tube when the sensor is completely mounted.
On version C and D, the connection is made
via the cable screen of the transducer cable
and the transducer tube.
Shielding of the sensor cables
The "Electromagnetic pollution“ from elec-
tronic actuators, power lines and transmitting
stations is often so considerable that the two-
wire cable of VEGASCAN to the sensors
must be shielded.