PR electronics 6350 Manuel Du Produit page 26

LERBAKKEN 10, 8410 RØNDE DENMARK.
connected device. Separately powered equipment needs a galvanic isolation to insure that the
intrinsically safe Fieldbus circuit remains passive.
The cable used to interconnect the devices needs to comply with the following parameters:
Loop resistance R': 15 ...150 /KM
Inductance per unit length L': 0.4...1mH/km
Capacitance per unit length C': 80 ...200 nF/km
C' = C' line/line + 0.5 C' line/screen, if both lines are floating
or
C'= C' line/line + C' line/screen, if the screen is connected to one line
Length of spur Cable: max. 30m
Length of trunk cable: max. 1Km
Length of splice: max. 1m
Terminators
At each end of the trunk cable an approved line terminator with the following parameters is suitable:
R = 90 ...100 
C = 0 ...2.2 F.
System evaluation
The number of passive devices like transmitters, actuators, connected to a single bus segment is
not limited due to I.S. reasons. Furthermore, if the above rules are respected, the inductance and
capacitance of the cable need not to be considered and will not impair the intrinsic safety of the
installation.
The sensor circuit is not infallibly galvanic isolated from the Fieldbus input circuit. However, the
galvanic isolation between the circuits is capable of withstanding a test voltage of 500Vac during 1
minute.
Installation Notes For FISCO and Entity Concepts:
1. The Intrinsic Safety Entity concept allows the interconnection of FM / CSA Approved
Intrinsically safe devices (Div 1 or Zone 0 or Zone1) and non.incendive apparatus (Div 2 or
Zone 2) ,with entity parameters not specifically examined in combination as a system when:
Uo or Voc or Vt  Vmax, Io or Isc or It  Imax, Po  Pi.
Ca or Co  Ci + Ccable, La or Lo  Li + Lcable, Po  Pi.
2. The Intrinsic Safety FISCO concept allows the interconnection of FM / CSA Approved
Intrinsically safe devices with FISCO parameters not specifically examined in combination as
a system when:
Uo or Voc or Vt  Vmax, Io or Isc or It  Imax, Po  Pi.
3. Dust-tight conduit seals must be used when installed in Class II and Class III environments.
4. Control equipment connected to the Associated Apparatus must not use or generate more
than 250 Vrms or Vdc.
5. Installation should be in accordance with ANSI/ISA RP12.6 (except chapter 5 for FISCO
Installations) "Installation of Intrinsically Safe Systems for Hazardous (Classified) Locations"
and the National Electrical Code® (ANSI/NFPA 70) Sections 504 and 505.
6. The configuration of associated Apparatus must be Factory Mutual Research or CSA
Approved under the associated concept.
7. Associated Apparatus manufacturer's installation drawing must be followed when installing
this equipment.
Revision date:
2014-12-11
26
WWW.PRELECTRONICS.COM
Version Revision
V3R0
6350V104-FR
6350QE02
Page:
5/6