Ohmart Vega VEGAPULS 67, Информация о продукте

Страница: 11 / 28

4 E lectrical connection
4 . 1 G eneral prerequisites
T he supply voltage range can di ff er depending on the instrument
version . Y ou can fi nd exact speci fi cations in chapter " T echnical
data " .
T ake note of country - speci fi c installation standards ( e . g . the VDE
regulations in G ermany ) as well as prevailing safety regulations
and accident prevention rules .
I n hazardous areas you should take note of the appro -
priate regulations , conformity and type approval certi fi -
cates of the sensors and power supply units .
4 . 2 V oltage supply
4 … 20 m A / HART two - wire
T he VEGA power supply units VEGATRENN 149 AE x , VEGAS -
TAB 690 , VEGADIS 371 as well as VEGAMET signal condition -
ing instruments are suitable for power supply . W hen one of these
instruments is used , a reliable separation of the supply circuits
from the mains circuits according to DIN VDE 0106 part 101 is
ensured for the sensor .
4 … 20 m A / HART four - wire
P ower supply and current output are carried on two separate
connection cables .
T he standard version can be operated with an earth - connected
current output , the E xd version must be operated with a fl oating
output .
T he instrument is designed in protection class I . T o maintain this
protection class , it is absolutely necessary that the ground con -
ductor be connected to the internal ground conductor terminal .
P ro fi bus PA
P ower is supplied by a P ro fi bus DP / PA segment coupler or a
VEGALOG 571 EP input card .
F ig . 15 : I ntegration of instruments in a P ro fi bus PA system via segment coupler DP /
PA or data recording systems with P ro fi bus PA input card
F oundation F ieldbus
P ower supply via the H 1 F ieldbus cable .
4 . 3 C onnection cable
G eneral
T he sensors are connected with standard cable without screen .
A n outercable diameterof 5 … 9 mm ensures theseal e ff ect of the
cable entry .
4 … 20 m A / HART two - wire and four - wire
I f electromagnetic interference is expected which is above the
test values of EN 61326 for industrial areas , screened cable
should be used . I n HART multidrop mode the use of screened
cable is generally recommended .
P ro fi bus PA , F oundation F ieldbus
T he installation must be carried out according to the appropriate
bus speci fi cation . T he sensor is connected respectively with
screened cable according to the bus speci fi cation . M ake sure
that the bus is terminated via appropriate terminating resistors .
F or power supply , an approved installation cable with PE con -
ductor is also required .
I n E x applications , the corresponding installation regu -
lations must be noted for the connection cable .
4 . 4 C onnection of the cable screen and
grounding
I f screened cable is necessary , the cable screen must be con -
nected on both ends to ground potential . I f potential equalisation
currents are expected , the connection on the evaluation side
must be made via a ceramic capacitor ( e . g . 1 n F , 1500 V ).
P ro fi bus PA , F oundation F ieldbus
I n systems with potential separation , the cable screen is con -
nected directly to ground potential on the power supply unit , in
the connection box and directly on the sensor .
I n systems without potential equalisation , connect the cable
screen directly to ground potential only at the power supply unit
and at the sensor - do not connect to ground potential in the
connection box or T - distributor .
E lectrical connection
R adar – L evel measurement of bulk solids 11
31488
-
EN
-
070320