Endress+Hauser PROline promag 53 II3G Mise En Service page 33

PROline Promag 53 FOUNDATION Fieldbus
Endress+Hauser
Bus cable for FOUNDATION Fieldbus
The Fieldbus FOUNDATION defines four different types of cable in the specification cre-
ating the physical transmission layer (FF-816) which is analogous to IEC 61158-2. A two-
core cable is always specified.
The electrical data has not been specified but determines important characteristics of
the design of the fieldbus, such as distances bridged, number of participants, electro-
magnetic compatibility, etc.
Two of the four cable types in the standard are specified in the following table.
Cable construction
Core cross-section (nominal)
Loop resistance (direct current)
Impedance at 31.25 kHz
Attenuation constant at 39 kHz
Capacitive unsymmetry
Envelope delay distortion
(7.9 through 39 kHz)
Degree of voltage of shielding
Max. bus segment length (inc. spur lines)
Tab. 1: Cable types
We recommend the use of cables meeting the minimum requirements of type A as
transmission medium, particularly for the installation of new systems. The recom-
mended network expansion is made up of the length of the main cable and the length
of all spurs. The line between distribution box and field device is described as a spur.
The maximum length of a spur depends on the number of spurs (>1 m). A maximum of
four field devices can be connected to a spur.
Number of spurs
Max. length per spur
Tab. 2: Table of possible spur line lengths
.
The following table shows examples of FOUNDATION Fieldbus bus cables (type A)
from various manufacturers.
Supplier
Belden
Kerpen
Siemens
Tab. 3: Possible cable suppliers
Cable type A
(reference)
twisted pair, shielded
2
0.8 mm (AWG 18)
44 Ω /km
100 Ω ± 20%
3 dB/km
2 nF/km
1.7 µ s/km
90%
1900 m
1...12 13...14
120 m 90 m
Model
3076
FB-02YS (St+C) Y-FL
SIMATIC NET
bus cable

Cable type B
one or more twisted pairs,
fully shielded
2
0.32 mm (AWG 22)
112 Ω /km
100 Ω ± 30%
5 dB/km
2 nF/km
**
**
1200 m
15...18 19...24
60 m 30 m
Order number
–
74220004
6XV1830-5BH10
25...32
1 m
11