4
E
lectrical connection
4
.
1
G
eneral requirements
T
he supply voltage range can di
ff
er depending on the instrument
version
.
T
he exact range is stated in the
"
T
echnical data
"
.
T
ake note of country
-
speci
fi
c installation standards
(
e
.
g
.
the
VDE
regulations in
G
ermany
)
as well as prevailing safety regulations
and accident prevention rules
.
I
n hazardous areas you should take note of the appro
-
priate regulations
,
conformity and type approval certi
fi
-
cates of the sensors and power supply units
.
4
.
2
V
oltage supply
G
eneral
P
ower supply and current signal are carried over the same two
-
wire connection cable
.
T
he requirements on the power supply are
stated in the
T
echnical
D
ata of this
P
roduct
I
nformation manual
.
4
…
20
m
A
/
HART
two
-
wire
T
he
VEGA
power supply units
VEGATRENN
149
AE
x
,
VEGAS
-
TAB
690
,
VEGADIS
371
as well as
VEGAMET
signal condition
-
ing instruments are suitable for power supply
.
W
hen one of these
instruments is used
,
a reliable separation of the supply circuits
from the mains circuits acc
.
to
DIN VDE
0106
part
101
is ensured
for
VEGABAR
.
P
ro
fi
bus
PA
P
ower is supplied by a
P
ro
fi
bus
DP
/
PA
segment coupler or a
VEGALOG
571
EP
input card
.
F
ig
.
11
:
I
ntegration of instruments in a
P
ro
fi
bus
PA
system via segment coupler
DP
/
PA
or data recording systems with
P
ro
fi
bus
PA
input card
F
oundation
F
ieldbus
P
ower supply via the
H
1
F
ieldbus cable
.
4
.
3
C
onnection cable
G
eneral
T
he sensors are connected with standard cable without screen
.
A
n outercable diameterof
5
…
9
mm ensures theseal e
ff
ect of the
cable entry
.
4
…
20
m
A
/
HART
two
-
wire and four
-
wire
I
f electromagnetic interference is expected which is above the
test values of
EN
61326
for industrial areas
,
screened cable
should be used
.
I
n
HART
multidrop mode the use of screened
cable is generally recommended
.
P
ro
fi
bus
PA
,
F
oundation
F
ieldbus
T
he installation must be carried out acc
.
to the appropriate bus
speci
fi
cation
.
VEGABAR
is connected respectively with
screened cable acc
.
to the bus speci
fi
cation
.
P
ower supply and
digital bus signal are transmitted via the same two
-
wire connec
-
tion cable
.
M
ake sure that the bus is terminated via appropriate
terminating resistors
.
I
n
E
x applications
,
the corresponding installation regu
-
lations must be noted for the connection cable
.
4
.
4
C
able screening and grounding
I
f screened cable is necessary
,
the cable screen must be con
-
nected on both ends to ground potential
.
I
f potential equalisation
currents are expected
,
the connection on the evaluation side
must be made via a ceramic capacitor
(
e
.
g
.
1
n
F
,
1500
V
).
P
ro
fi
bus
PA
,
F
oundation
F
ieldbus
I
n systems with potential separation
,
the cable screen is con
-
nected directly to ground potential on the power supply unit
,
in
the connection box and directly on the sensor
.
I
n systems without potential equalisation
,
connect the cable
screen directly to ground potential only at the power supply unit
and at the sensor
-
do not connect to ground potential in the
connection box or
T
-
distributor
.
4
.
5
W
iring plans
S
ingle chamber housing
I2C
Display
1
1
2
5
6
7
8
F
ig
.
12
:
C
onnection
HART
two
-
wire
,
P
ro
fi
bus
PA
,
F
oundation
F
ieldbus
1
P
ower supply and signal output
E
lectrical connection
H
ydrostatic
–
L
evel and pressure measurement
9
29235
-
EN
-
060411