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

26 Capacitive electrodes EL - Profibus PA
Electrical connection
Connection 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
ground terminal
Sensor
Screen
Overvoltage arrester
in metal or
plastic housing
Screen
Non-Ex area
Switching cabinet/Control room
Signal
condition-
ing
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 con-
nected to the potential equalisation).
Test voltage of the cable "A" ³ 1500 V AC.
B
A cable acc. to VDE, if necessary with metal cover or shielding, must be used between control room and
overvoltage arrester (connect metal cover or shielding, if necessary, only on one end of the cable to
earth or PA).
Test voltage of the cable "B"
≥
500 V AC.
Vessel
Zone 0
to the potential
equalisation cable
Screen -if necessary- connect
only on one cable end to ground
or PA
min.
4 mm
2 Cu