Ii d d, Di i, 3 installation in the hazardous area, bus cable – KROHNE IFC 090 i Converter FOUNDATION FIELDBUS User Manual
Page 5
Supplementary Documentation
Page 5 of 44
IFC090, IFC090 i with FF
Installation and Operation
IFC090 FF 01/2006
KROHNE Messtechnik GmbH & Co. KG · Ludwig-Krohne-Str. 5 D-47058 Duisburg
Tel.: 0203-301 309 Fax: 0203-301389 · E-mail: [email protected]
Foundation Fieldbus with Current Output (passive)
Foundation Fieldbus with Binary Output (passive)
Non Ex Version
Non Ex Version
Outputs intrinsically safe
Outputs intrinsically safe
2.3
Installation in the Hazardous Area, Bus Cable
We recommend that a Foundation Fieldbus network in the hazardous area should be projected in accordance
with PTB’s FISCO model. The FISCO-Model is based on the following conditions:
• all electrical components which should be connected to the bus must be approved according to the FISCO
model (even the termination)
• the maximum cable length should not exceed 1000 m,
• the values of the cable are within the following ranges: R´=15...150Ω/km; L´=0,4...1mH/km;
C´=80...200nF/km, other limitations for the cable than the FISCO limitations are not existent. Nevertheless, a
twisted pair and shielded cable is strongly recommended. Example: a good quality cable could have the
following data: 44
Ω/km, <90nF/km, <3dB attenuation at 39 kHz and 100 Ohm impedance at 31,25kHz.
• the approved input values of the field devices (Uo, Io, Po) comply to the output values of the power supply
(e.g. segment coupler) according to UI
≤ Uo, II ≤ Io und PI ≤ Po.
current
output
fieldbus
power-
supply
D
D
I
I
U min
= 8V
U max = 30V
4-20mA
FE
FE
bus-
connection
I
I D D
current
output
fieldbus
power
supply
U min
= 8V
bus-
connection
U max = 30V
4-20mA
switching
output
fieldbus
power-
supply
B
1
B
1
bus-
connection
D
D
FE
FE
B
1
D D
switching
output
fieldbus
power
supply
bus-
connection
B
1
1