KROHNE SU 600 EN - Manual (Page 14)

5 Connecting to power supply
5.1 Preparing the connection
Always observe the following safety instructions:
l
Connect only in the complete absence of line voltage
l
If overvoltages are expected, overvoltage arresters
should be installed.
In hazardous areas you should take note of the
appropriate regulations, conformity and type approval
certificates of the sensors and power supply units.
The power supply can be 20 … 253 V AC, 50/60 Hz or
20 … 253 V DC.
Power supply of SU 600 is connected with standard
cable acc. to the national installation standards.
Standard two-wire cable without screening can be used
to connect sensors. If electromagnetic interference is
expected, screened cable must be used.
Connect the cable screen on both ends to ground
potential. In the sensor, the screen must be connected
directly to the internal ground terminal. The ground
terminal outside on the sensor housing must be
connected to the potential equalisation.
If potential equalisation currents are expected, the
screen connection on SU 600 must be made via a
ceramic capacitor (e.g. 1 nF, 1500 V). The low
frequency potential equalisation currents are thus sup-
pressed, but the protective effect against high frequency
interference signals remains.
Take note of the corresponding installation regulations
for Ex applications. In particular, make sure that no
potential equalisation currents flow over the cable
screen. In case of grounding on both sides this can be
achieved by the use of a capacitor or a separate
potential equalisation.
Note safety instructions
Take note of safety
instructions for Ex
applications
Select power supply
Select connection cable
Cable screening and
grounding
Select connection
cable for Ex appli-
cations
14 SU 600 - 4 … 20 mA signal conditioning
Connecting to power supply
30652
-EN
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