VEGA VEGAPULS 56V - Manual (Page 44)

44 VEGAPULS 56V
Electrical connection
5 Electrical connection
5.1 Connection and connection
cable
Safety information
Ensure that the instrument is in currentless
condition. Always switch off the power sup-
ply before you carry out terminal work on the
radar sensors. Protect yourself and the in-
strument, especially when you use sensors
which do not work with low voltage.
Skilled staff
Instruments which are not operated with a
protective low voltage must only be con-
nected by skilled staff.
Connection
A standard two-wire cable with max. 2,5 mm 2
can be used for connection. Very often the
"Electromagnetic pollution“ by electronic
actuators, energy lines and transmitting
stations is so considerable that the two-wire
cable should be screened.
We recommend to use a screening. This
screening prevents against future interfer-
ences (figure 1).
It is favourable to earth the screens on both
ends. However it must be noted that no earth
compensation currents flow via the sensor
cable screens (figure 2). Earth compensation
currents can be avoided by connecting the
cable screen in case of earthing on both
sides on one earthing side (e.g. in the
switching cabinet) via a capacitor (e.g.
0,1␣
µ
F; 250␣ V) to earth potential. Use a very
low impedance earth connection (foundation,
plate or mains earth).
Ex-protection
If an instrument is used in hazardous areas,
the appropriate regulations, conformity cer-
tificates and type approvals for systems in
Ex-areas must be noted (e.g. DIN␣ 0165).
Connection cable
Note that the connection cables must be speci-
fied for the expected operating conditions in
your systems. The cable must have an outer
diameter of 5␣ …␣ 9␣ mm (1/5 to 1/3␣ inch) or with
Ex␣ d-housing 3,1␣ …␣ 8,7␣ mm (0,12␣ …␣ 0,34␣ inch).
Otherwise the seal effect of the cable entry will
not be ensured.
Cables for intrinsically safe circuits must be
marked blue and must not be used for other
circuits.
Earth conductor terminal
On all VEGAPULS 56 sensors the earth con-
ductor terminal is galvanically connected to
the metal process connection.
5.2 Connection of the sensor
After having mounted the sensor in the mea-
suring position according to the instructions
in chapter "4 Mounting and installation“ loosen
the closing screw on top of the sensor. The
sensor cover with the optional display can
then be opened. Unscrew the compression
screw and shift the screw over the approx.
10 cm dismantled connection cable. The
compression screw of the cable entry is
protected with a safety lock-in position
against automatic loosening.
Now loop the cable through the cable entry
into the sensor. Screw the compression
screw again to the cable entry and clamp the
dismantled wires of the cable to the appropri-
ate terminal positions.
The terminals operate without terminal screw.
Press the white opening buckets with a small
screwdriver and insert the copper core of the
connection line into the terminal opening.
Check the position of the lines in the terminal
position by slightly pulling on the connection
lines.