Installation
20
13
-0
3
19
5.4.6
Cables
The bus line is specified in EN 50170 as line type A. It can be used in accordance
with the following table. The line parameters and lengths for line type B are also
specified in the two following tables. When planning a new plant, only line type A
should be used because of the higher total line length.
The line parameters are as follows:
*No longer use line type B if possible.
5.4.7
Transfer rates and line lengths
The permitted length of the transfer line in a bus segment is largely determined by
the following parameters:
■
Type of bus cable used
■
Transfer rate
■
External interference
■
Number of nodes
The maximum total line length of a bus segment, depending on the transfer rate
with the maximum number of stations (32) totals:
Parameter
Line type A
Line type B*
Cable construction
two-wire, twisted, screened
Distributed capacitance [pF/m]
< 30
< 60
Ripple resistance [
]
135 ... 165
100 ... 130
Loop resistance [
/km]
110
---
Wire cross-section [mm]
> 0,64
> 0,53
Line cross-section [mm
2
]
> 0.34
> 0.22
Note!
Use only screened, twisted-pair cables. The best possible EMC interference
immunity can only be achieved by using screened cables.
Baud rate in kbit/s
9.6
19.2
93.75
187.5
500
1500
3000,
6000,
12000
Line type A (in m)
1200
1200
1200
1000
400
200
100
Line type B (in m)
1200
1200
1200
600
200
---
---
Note!
The transfer length can be increased with the distribution among multiple bus
segments and the use of repeaters. A maximum of three repeaters can be used
between two communicating nodes.
