Endress+Hauser PROline prosonic flow 93 II2 GD Mode D'emploi page 53

PROline Prosonic Flow 93 FOUNDATION Fieldbus
Endress+Hauser
Bus cable for FOUNDATION Fieldbus
The Fieldbus FOUNDATION defines four different types of cable in the specification
creating 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...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 trans-
mission medium, particularly for the installation of new systems. The recommended net-
work 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 µs/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
–
74220001 (light blue)
74220004 (black)
6XV1830-5AH10 (light blue)
6XV1830-5BH10 (black)
25...32
1 m
15