Technical data

Network configuration
3.1 Configuring electrical networks
PROFIBUS Network Manual
42 System Manual, Edition 04/2009, C79000-G8976-C124-03
For a cable terminator to work it must be supplied with power. This means that the relevant
end device or RS-485 repeater must be supplied with power. As an alternative, the
PROFIBUS terminator can be used as permanent cable terminator.
Note
The power supply to terminating resistors must not be interrupted by turning off the end
device or repeater or by unplugging the bus connector or spur line. If uninterrupted power
supply to the terminating resistors cannot be guaranteed, the PROFIBUS terminator with its
own power supply must be used.
3.1.2 Segments for transmission speeds up to a maximum of 500 kbps
Transmission speeds up to a maximum of 500 kbps
The following maximum segment lengths can be implemented with the SIMATIC NET
PROFIBUS cables:
Table 3- 1 Possible segment lengths
Segment length for cable type
Transmission speed in
kbps
- 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
9.6 1000 m 900 m
19.2 1000 m 900 m
45.45 1000 m 900 m
93.75 1000 m 900 m
187.5 1000 m 700 m
500 400 m 400 m
The maximum permitted number of bus attachments (end devices, repeaters, OLMs, BT12 M,...) to
one segment is 32.
Length of the spur lines
If you do not fit the bus cable directly at the bus connector (for example, when using a
PROFIBUS-DP bus terminal), you must take into account the maximum possible spur line
length.
The table below shows the maximum permitted lengths of spur lines per segment: