5
C
onnecting to power supply
5
.
1
P
reparing the connection
A
lways observe the following safety instructions
:
l
C
onnect only in the complete absence of line voltage
l
I
f overvoltages are expected
,
overvoltage arresters should
be installed
.
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
.
T
he power supply can be
20
…
250
V AC
,
50
/
60
H
z or
20
…
72
V DC
.
P
ower supply of
SU
501
E
x is connected with standard cable
acc
.
to the national installation standards
.
S
tandard two
-
wire cable without screening can be used to
connect sensors
.
I
f electromagnetic interference is expected
,
screened cable must be used
.
C
onnect 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 outside on the
sensor housing must be connected to the potential equalisa
-
tion
.
I
f potential equalisation currents are expected
,
the screen
connection on
SU
501
E
x 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 interference 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
.
5
.
2
C
onnection procedure
M
ove to electrical connection and proceed as follows
:
1
S
nap the socket without
SU
501
E
x onto the carrier rail
N
ote safety instructions
T
ake note of safety
instructions for
E
x
applications
S
elect power supply
S
elect connection cable
C
able screening and groun
-
ding
S
elect connection
cable for
E
x applica
-
tions
12
SU
501
E
x
-
S
ignal conditioning instrument
C
onnecting to power supply
27953
-
EN
-
050616
