24
Capacitive electrodes EL 4 … 20 mA - compact
Electrical connection
A
B
2
1
E2
E1
A2
A1
2
1
A2
A1
E2
E1
Vessel with cathodic corrosion protection
(Ex)-area Zone 1
Not (Ex)-area
overvoltage
protection unit
mounted on
oscillator
Oscillator
b)
Capacitive electrodes with external overvoltage
protection unit
Scr
een
Cathodic tank pr
otection
2 … 24 V (object voltage)
CB
2-36
CAP
E32(H)EX
Exter
nal ear
th terminal
Inter
nal earth ter
minal
V
essel
Zone 0
Li, Ci of the oscillator with
overvoltage protection unit
Li = 0,27 mH
Ci = 8,5 nF
Contr
ol r
oom
either: Overvoltage
pr
otection inser
t
Signal
cond.
instr
.
or
safety
barrier
Type B62-36G
Li=0,15 mH
Ci=2,5 nF
Over
voltage pr
otection inser
t
Over
voltage pr
otection
instrument in metal
housing or plastic
housing. The metal
housing must be
mounted ear
th fr
ee
Exter
nal ear
th terminal
Inter
nal earth ter
minal
Cathodic tank pr
otection
2 … 24 V (object voltage)
Isolated line
min. 4 mm
2
V
essel
Zone 0
Oscillator
Li=0,12 mH
Ci=6 nF
Scr
een
CAP
E32
(H)Ex
Type
B62-36G
Li=0,15 mH
Ci=2,5 nF
Between contr
ol r
oom and over
voltage pr
otection
system a suitable cable must be used, if
necessar
y with metal cover or scr
een. Metal
cover or scr
een - if necessar
y - must be only
connected to the over
voltage protection system
on the electr
ode side. The cable must have an
outer isolation. T
est voltage of the cable A:
≥
500
V AC
Between overvoltage pr
otection system and
capacitive electr
ode a suitable cable with metal
cover
, screen or a suitable cable with metal
pr
otection tube must be used (metal cover or
pr
otection tube must not be ear
thed).
Test voltage of the cable B:
≥
1500 V AC
a)
Capacitive electrodes with integral overvoltage
protection unit type CB 2-36
A
B
