VEGA VEGAWELL 72 4 … 20 mA_HART PT 100 - Manual (Page 17)

5 C onnecting to power supply
5 .1 Preparing the connection
A lways keep in mind the following safety instructions:
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C
onnect only in the complete absence of line voltage
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I f overvoltage surges are expected, overvoltage arresters
should be installed
Tip:
W
e recommend the following VEGA overvoltage arresters:
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B 63-48 ( use in plastic housing of VEGAWELL 72)
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ÜSB 62-36G.X (use in a separate housing)
I
n hazardous areas you should take note of the appropriate
regulations, conformity and type approval certificates of the
sensors and power supply units.
P ower supply and current signal are carried on the same two-
wire cable. The voltage supply range can differ depending on
the instrument version.
D ata for power supply are specified in chapter "Technical
data".
P
rovide 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 VEGAWELL 72.
B ear in mind the following factors regarding supply voltage:
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O
utput voltage of the power supply unit can be lower under
nominal load (with a sensor current of 20.5 mA or 22 mA in
case of fault message)
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I
nfluence of additional instruments in the circuit (see load
values in chapter "Technical data")
T he 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.
Note safety instructions
Take note of
safety instruc-
tions for Ex ap-
plications
Select power supply
Selecting connection
cable
VEGAWELL 72 • 4 … 20 mA/HART PT 17
5 C onnecting to power supply
34360
-
EN
-080806