5
C
onnecting to power supply
5
.
1
P
reparing the connection
A
lways keep in mind the following safety instructions
:
l
C
onnect only in the complete absence of line voltage
l
I
f overvoltage surges are expected
,
overvoltage arresters should
be installed
T
ip
:
W
e recommend using
VEGA
overvoltage arresters
B
63
-
48
and
Ü
SB
62
-
36
G
.
X
.
I
n hazardous areas you should take note of the appropriate
regulations
,
conformity and type approval certi
fi
cates of the sensors
and power supply units
.
S
upply voltage and current output are carried on separate two
-
wire
connection cables if reliable separation is required
.
T
he supply voltage
range can di
ff
er depending on the instrument version
.
T
he data for power supply are speci
fi
ed in chapter
"
T
echnical data
"
.
T
he standard version can be operated with an earth
-
connected current
output
,
the
E
xd version must be operated with a
fl
oating output
.
T
his instrument is designed in protection class
I
.
T
o maintain this
protection class
,
it is absolutely necessary that the ground conductor
be connected to the internal ground terminal
.
T
ake note of the general
installation regulations
.
A
lways connect the instrument to vessel ground
(
potential equal
-
isation
)
or in case of plastic vessels to the next ground potential
.
F
or
this purpose there is a ground terminal on the side of the instrument
housing
.
F
or power supply
,
an approved installation cable with
PE
conductor is
necessary
.
T
he
4
…
20
m
A
current output is connected with standard two
-
wire
cable without screen
.
I
f electromagnetic interference is expected
which is above the test values of
EN
61326
for industrial areas
,
screened cable should be used
.
U
se cable with round cross
-
section
.
A
cable outer diameter of
5
…
9
mm
(
0
.
2
…
0
.
35
in
)
ensures the seal e
ff
ect of the cable gland
.
I
f you are
using cable with a di
ff
erent diameter or cross
-
section
,
exchange the
seal or use a suitable cable gland
.
N
ote safety instructions
T
ake note of sa
-
fety instructions
for
E
x applica
-
tions
V
oltage supply
C
onnection cable
VEGAFLEX
66
•
4
…
20
m
A
/
HART
four
-
wire
17
5
C
onnecting to power supply
34170
-
EN
-
100427
