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 according to
P
ro
fi
bus speci
fi
cations
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
.
P
ower is supplied via a
P
ro
fi
bus
DP
/
PA
segment coupler
.
T
he power
supply range can di
ff
er depending on the instrument version
.
T
he
exact range is stated in the
"
T
echnical data
"
.
IPT
-
1
*
V
ers
.
4
.
0
is connected with screened cable according to the
P
ro
fi
bus speci
fi
cation
.
P
ower supply and digital bus signal are carried
over the same two
-
wire connection cable
.
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
.
P
lease make sure that your installation is carried out according to the
P
ro
fi
bus speci
fi
cation
.
I
n particular
,
make sure that the termination of
the bus is done with appropriate terminating resistors
.
I
n systems with potential equalisation
,
connect the cable screen
directly to ground potential at the power supply unit
,
in the connection
box and at the sensor
.
T
he screen in the sensor must be connected
directly to the internal ground terminal
.
T
he ground terminal outside on
the housing must be connected to the potential equalisation
(
low
impedance
).
I
n systems without potential equalisation
,
connect the cable screen
directly to ground potential at the power supply unit and at the sensor
.
I
n the connection box or
T
-
distributor
,
the screen of the short stub to
the sensor must not be connected to ground potential or to another
cable screen
.
T
he cable screens to the power supply unit and to the
next distributor must be connected to each other and also connected
to ground potential 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 interference signals remains
.
T
he total capacitance of the cable and of all capacitors must not exceed
10
n
F
in
E
x applications
.
N
ote safety instructions
T
ake note of
safety instruc
-
tions for
E
x ap
-
plications
S
elect power supply
S
electing connection
cable
C
able screening and
grounding
P
rocess pressure transmitter
IPT
-
11
V
ers
.
4
.
0
-
ceramic sensor
•
P
ro
fi
bus
PA
13
5
C
onnecting to power supply
31547
-
EN
-
081211
