F08 Installation & Programming Manual
Document No: LT0082
Application Considerations
5.2.4 ISOLATING
REPEATERS
Two isolating repeaters are specified for use with F08:
Pepperl & Fuchs' KFDO-CS-Ex 1.51P and
Pepperl & Fuchs' KFDO-CS-Ex 2.51P
For these isolating repeaters the total capacitance and inductance of the detectors and
cables on the IS circuit must be less than that specified in Table 5.2.1.
The gases and vapours in each gas group are listed in IEC 79-12.
GAS GROUP
MAX. CAPACITANCE MAX.
INDUCTANCE
IIA
1.04uF
33.6mH
IIB
0.39uF
12.6mH
IIC
0.13uF
4.2mH
Table 5.2.1
Maximum Capacitance & Inductance Per IS Circuit
For isolating repeaters, the cable core capacitance can be used, rather than core to earth
which, for bunched conductors on metal trays, may be higher. (Note that for Zener barriers,
the core to earth capacitance is relevant). The values used in this section for a typical TPS
pair, or multicore cable (unshielded) are:
TPS
C = 100nF/km (i.e. 100 pF/m),
L = 0.8mH/km
Cable manufacturers may quote differing values for specific cables.
It is the responsibility of the System Engineer to check that the cable used has values less
than or equal to the above values, and that the total capacitance and inductance for each
circuit meet the requirements.
The values specified for the detectors are shown in Table 5.2.2.
DETECTOR CAPACITANCE
INDUCTANCE RESISTANCE
(FW ONLY)
1uH (0.001mH)
1nF
C29BEx/Z94C
1.5Mh
3.3nF
R24BEx
1.5nF
MS302Ex
0.62mH/km
84nF/km
FW68
100
Ω
/km
0.83mH/km
66nF/km
FW105
100
Ω
/km
0.89mH/km
57nF/km
FW180
100
Ω
/km
Table 5.2.2
Capacitance & Inductance Per IS Detector
Page 5-6
24 March 2006
Issue 3.04
Summary of Contents for F08
Page 48: ......
