VEGA VEGAWELL 52 4 … 20 mA_HART Pt 100 - Manual (Page 15)

5 Connecting to power supply
5 .1 Preparing the connection
G
enerally connect the instrument only in the complete absence of line
voltage.
T he instrument is equipped with an integrated overvoltage protection.
F or additional protection of the signal circuit, we recommend further
external overvoltage arresters:
l T ype B63-48 (use with VEGAWELL 52 with plastic housing) or
l T ype ÜSB 62-36G.X (use in a separate housing)
I n hazardous areas you must take note of the respective 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.
T he data 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
52.
K eep in mind the following additional factors that influence the
operating voltage:
l 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)
l 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.
U se 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.
W e generally recommend the use of screened cable for HART
multidrop mode.
Safety instructions
Take note of sa-
fety instructions
for Ex applica-
tions
Select power supply
Select connection cable
VEGAWELL 52 • 4 … 20 mA/HART Pt 15
5 C onnecting to power supply
35402
-
EN
-111021