Connecting To Power Supply; Preparing The Connection - Vega VEGABAR 12 Operating Instructions Manual

Note safety instructions
Select power supply
Select connection cable
Cable screening and
grounding
VEGABAR 12

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
l
If voltage surges are expected, install overvoltage arresters
l
The supply voltage and the current signal are carried on the same two-
wire connection cable.
Provide a reliable separation between the supply circuit and the mains
circuits according to DIN VDE 0106 part 101.
Keep in mind the following additional factors that influence the
operating voltage:
Output voltage of the power supply unit can be lower under
l
nominal load (with a sensor current of 3.6 mA in case of fault
message)
Influence of additional instruments in the circuit (see load values in
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chapter "Technical data")
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.
If potential equalisation currents are expected, the connection on the
processing side 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 interfer-
ence signals remains.
Warning:
Within galvanic plants as well as vessels with cathodic corrosion
protection there are considerable potential differences. Considerably
equalisation currents can be caused via the cable scrren when the
screen is earthed on both ends. To avoid this, the cable screen must
only connected to ground potential on one side of the switching
cabinet in such applications. The cable screen must not be connected
to the internal ground terminal in the sensor and the outer ground
terminal on the housing not to the potential equalisation!
5 Connecting to power supply
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