Technical data

Network configuration
3.1 Configuring electrical networks
PROFIBUS Network Manual
46 System Manual, Edition 04/2009, C79000-G8976-C124-03
3.1.4 Segments for transmission speeds up to a maximum of 12 Mbps
Transmission speeds up to a maximum of 12 Mbps
The following maximum segment length can be implemented with the SIMATIC NET
PROFIBUS cable:
Table 3- 6 Possible segment lengths
Segment length for cable type
Transmission speed in
Mbps
- FC standard cable
- FC standard cable IS GP
- FC robust cable
- FC FRNC cable
- FC food cable
- FC underground cable
- SIENOPYR-FR marine cable
- FC trailing cable
- PROFIBUS flexible cable
- PROFIBUS festoon cable
- PROFIBUS torsion cable
3 100 m 100 m
6 100 m 100 m
12 100 m 100 m
When planning segments for transmission speeds from 3 Mbps to a maximum of 12 Mbps,
the following factors must be taken into account:
● The maximum length of a segment must not exceed 100 m.
● The maximum number of bus attachments (nodes, OLMs, RS485 repeaters,...) in one
segment is restricted to 32.
● The use of passive spur lines is not allowed.
● To attach end devices to bus segments, only the bus connectors permitted for 12 Mbps
or the BT12M bus terminal can be used.
● To attach a programming device or PC via a spur line, only the "SIMATIC S5/S7
connecting cable, 12 Mbps, order no. 6ES7 901-4BD00-0XA0" can be used.
Note
If several bus connectors are used at short electrical intervals (in other words, the cable
length between adjacent connectors is less than 1 m, for example several slaves in one
cabinet), you should avoid the situation where several bus connectors are disconnected
at the same time for a longer period. Disconnecting more than one bus connector does
not necessarily mean errors but may well reduce the reliability (immunity to noise) of a
segment.