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5 Connecting to power supply
SU 600 Ex • 4 … 20 mA signal conditioning instrument
30653-EN-150129
5 Connecting to power supply
5.1 Preparing the connection
Always keep in mind the following safety instructions:
•
Connect only in the complete absence of line voltage
•
If overvoltage surges are expected, overvoltage arresters should
be installed
In hazardous areas you must take note of the respective 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.
The voltage supply of SU 600 Ex is connected with standard cable
according to the national installation standards.
The instrument is connected with standard two-wire cable without
screen. If electromagnetic interference is expected which is above the
test values of EN 61326 for industrial areas, screened cable should
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 connec-
tion on the side of SU 600 Ex must be made via a ceramic capacitor
(e. g. 1 nF, 1500 V). The low frequency potential equalisation currents
are thus suppressed, but the protective effect against high frequency
interference signals remains.
Take note of the corresponding installation regulations for Ex applica-
tions. 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.
5.2 Connection procedure
Proceed as follows:
1. Mount SU 600 Ex
2. Connect sensor cable to terminal 1 and 2, and where applicable,
connect the screen
3. Connect power supply (switched off) to terminal 5 and 6
4. If necessary, connect fail safe and operating relay as well as cur-
rent output
The electrical connection is finished.
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 applica-
tions
