VEGA Capacitive electrodes EK Profibus PA - Manual (Page 26)

26 Capacitive electrodes EK - Profibus PA
Electrical connection
Wiring example for the installation of an Ex system on vessels without cathodic
corrosion protection
The following overvoltage arrester can be used:
----- B62-30 W:
B62-30 W: B62-30 W: B62-30 W: B62-30 W: 9 … 36 V DC, max. 1 A
2
1 E2
E1 E2
E1 A2
A1 A2
A1
B A
B62-30 W B62-30 W
Ex area, zone 1 or zone 2
oscillator
transmitter
external earth
terminal
sensor
shielding
overvoltage arrester
in metal or plastic
housing
screen
Non Ex area
switch cabinet/control room
signal
conditioning
instrument
or safety
barrier
optionally:
overvoltage arrester
A
A cable with either metal cover, shielding or metallic protection tube according to VDE must be used
between overvoltage arrester and transmitter (metal cover, shielding or protection tube must be
connected with the potential equalisation).
Test voltage of the cable "A" ³ 1500 V AC.
B
A cable according to VDE must be used between control room and overvoltage arrester, if necessary with
metal cover or shielding (if necessary, connect metal cover or shielding only on one end of the cable with
earth or PA).
Test voltage of the cable "B"
≥
500 V AC.
vessel
zone 0
to potential
equalisation line
- if necessaryt - connect screen
only on one end of the cable with
earth or PA
min.
4 mm
2 Cu