I
f screened cable is necessary
,
connect the cable screen on both ends
to ground potential
.
I
n the sensor
,
the screen must be connected
directly to the internal ground terminal
.
T
he ground terminal on the
outside of the housing must be connected to the potential equalisation
(
low impedance
).
I
f potential equalisation currents are expected
,
the connection on the
processing side must be made via a ceramic capacitor
(
e
.
g
.
1
n
F
,
1500
V
).
T
he low frequency potential equalisation currents are thus
suppressed
,
but the protective e
ff
ect against high frequency interfer
-
ence signals remains
.
T
ake note of the corresponding installation regulations for
E
x
applications
.
I
n particular
,
make sure that no potential equalisation
currents
fl
ow over the cable screen
.
I
n case of grounding on both sides
this can be achieved by the use of a capacitor or a separate potential
equalisation
.
W
ith the
E
xd version
,
the minus side of the signal output is galvanically
connected to ground via protective diodes
.
W
hen connecting the
instrument to a grounded
PLC
,
equalising currents can
fl
ow in case of
potential di
ff
erences which can cause malfunctions
.
M
ake sure that
there is su
ffi
cient potential equalisation from the system side or realise
the connection via switching ampli
fi
er
.
5
.
2
C
onnection procedure
P
roceed as follows
:
1
U
nscrew the housing cover
2
L
oosen compression nut of the cable entry
3
R
emove approx
.
10
cm
(
4
in
)
of the cable mantle
(
current output
),
strip approx
.
1
cm
(
0
.
4
in
)
insulation from the ends of the individual
wires
4
I
nsert the cable into the sensor through the cable entry
5
L
ift the opening levers of the terminals with a screwdriver
6
I
nsert the wire ends into the open terminals according to the wiring
plan
7
P
ress down the opening levers of the terminals
,
you will hear the
terminal spring closing
8
C
heck the hold of the wires in the terminals by lightly pulling on
them
9
C
onnect the screen to the internal ground terminal
,
connect the
outer ground terminal to potential equalisation
10
T
ighten the compression nut of the cable entry
.
T
he seal ring must
completely encircle the cable
11
C
onnect the lead cable for power supply in the same way
according to the wiring plan
,
in addition connect the ground
conductor to the inner ground terminal
.
C
able screening and
grounding
I
nstallation with
E
x applications
18
VEGAFLEX
66
•
4
…
20
m
A
/
HART
four
-
wire
5
C
onnecting to power supply
34170
-
EN
-
100427
