Connecting To Power Supply; Preparing The Connection - Vega VEGABAR 14 Operating Instructions Manual

Note safety instructions
Take note of sa-
fety instructions
for Ex applica-
tions
Select power supply
Select connection cable
Cable screening and
grounding
VEGABAR 14

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
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If voltage surges are expected, install overvoltage arresters
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Tip:
We recommend VEGA overvoltage arrester ÜSB 62-36G.X.
In hazardous areas you must take note of the respective regulations,
conformity and type approval certificates of the sensors and power
supply units.
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.
VEGA power supply units VEGATRENN 149AEx, VEGASTAB 690,
VEGADIS 371 as well as all VEGAMETs meet this requirement. When
using one of these instruments, protection class III is ensured for
VEGABAR 14.
Keep in mind the following additional factors that influence the
operating voltage:
Output voltage of the power supply unit can be lower under
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nominal load (with a sensor current of 20.5 mA or 22 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.
Use cable with round cross-section. A cable outer diameter of 5 ... 9 mm
(0.2 ... 0.35 in) ensures the seal effect of the cable gland. If you are
using cable with a different diameter or cross-section, exchange the
seal or use a suitable cable gland.
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.
5 Connecting to power supply
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