Power repeater / power supply according to IEC 61158-2
instrumentFOUNDATION FieldbusIntroduction to intrinsic safety for
Subject to reasonable modifications due to technical advances.
Copyright Fuchs, Printed in Germany
Fuchs Group • Tel.: Germany (06 21) 7 76-0 • USA (330) 4 25 35 55 • Singapore 7 79 90 91 • Internet http://www.pepperl-fuchs.com
D
a
te
of
is
su
e1
2.
02
.2
00
2
10
Power repeaters with an intrinsically safe interface (KLD2-PR-Ex1.IEC1 and KLD2-
PR2-Ex1.IEC1) provide a maximum basic current of 100 mA at a minimal output volta-
ge of 12.8 V. Power can be supplied to as many as 10 field devices from these power
repeaters.
Given the requirement that items 1 through 9 are all fulfilled, there is no need to consi-
der inductance and capacitance.
4.2
The Entity model
The Entity model is based on the observation that the cable represents concentrated
inductance and capacitance. The result is that less electrical power can be transmit-
ted into the area subject to the risk of explosion when compared with the FISCO mo-
del. The values for Power Repeaters KLD2-PR-Ex1.IEC and
KLD2-PR2-Ex1.IEC are 10.6 V and 70 mA. The result of this is that only 6 stations
can be operated on a bus segment.
For the Ex values of the power repeaters, please refer to the EC Declaration of Con-
formity PTB 00 ATEX 2036 or FM Approval Report J.I.3008872.
The points enumerated in Section 4.1 items 1 through 9 apply equally well to the Enti-
ty model, with the exception of Item 5. According to the Entity model the internal in-
ductance of a field device must be less than 20 µH.
If the verification of Intrinsic Safety is made for the FISCO model, it is
sufficient to demonstrate that the values U
i
, I
i
and P
i
are greater than or
equal to the values U
o
, I
o
and P
o
of the power repeater for each instru-
ment.
FOUNDATION Fieldbus field devices that are approved according
toprofile 111 or 112 , must not be connected to power repeaters KLD2-
PR-Ex1.IEC1 and KLD2-PR2-Ex1.IEC1.
Field bus instruments that are certified according to the FISCO model
described in section 4.1, can be operated on the power repeaters that
are certified for the Entity model.
