28
Setting up a PROFIBUS network
Section 2-5
of PROFIBUS devices in such a network is then 122. The figure below shows
an example of a two-segment network.
Tree Topology
The use of repeaters allows the extension of three or more Linear Bus seg-
ments into a Tree topology. In a tree topology more than three repeaters are
allowed, provided that there are no more than three repeaters between any
two devices in the network. The following figure presents an example of a net-
work with more than three segments and repeaters.
Cable Type
The PROFIBUS standard EN 50170 specifies Type A shielded, twisted- pair
cable as the recommended cable type for use in an RS-485 based PROFI-
BUS network. This cable type has the following characteristics:
Station 2
Station 3
Station 31
Repeater
Station 63
Station 33
Station 32
Termination
Termination
Termination
Termination
OMRON
SYSMAC CS1G
PROGRAMMABLE
CONTROLLER
Station 1
Segment 1
Max. 31 stations
Segment 2
Max. 31 stations
M / S
M / S
M / S
M / S
Segment 3
Max. 28 stations
Segment 4
Max. 31 stations
Segment 5
Max. 30 stations
Segment 6
Max. 31 stations
M / S
R
R
R
R
M / S
R
Master or slave station
Repeater
Termination
Max. total number of stations = 126
M / S
R