Siemens SIMATIC S7-400 Hardware And Installation Manual page 136

Networking
Optical PROFIBUS-DP network in partyline topology
The optical PROFIBUS-DP network with nodes that have an integrated fiber-optic
cable interface has a partyline topology. The PROFIBUS nodes are
interconnected in pairs by means of Duplex fiber-optic cables.
Up to 32 PROFIBUS nodes with a fiber-optic cable interface can be
series-connected in an optical PROFIBUS-DP network. If a PROFIBUS node fails,
as a result of the partyline topology none of the downstream DP slaves can be
accessed by the DP master.
Programming S7-400 with IM 467 FO
device/PC/OP
PROFIBUS
cable
OBT
Figure 5-3 Optical PROFIBUS-DP network with nodes that have an integrated fiber-optic cable interface
Transmission rate
The following transmission rates are possible when the optical PROFIBUS-DP
network is operated with a partyline topology:
9.6 kbps, 19.2 kbps, 45.45 kbps, 93.75 kbps, 187.5 kbps, 500 kbps, 1.5 Mbps and
12 Mbps
PROFIBUS Optical Bus Terminal (OBT)
A PROFIBUS node can be connected to the optical PROFIBUS-DP network via a
PROFIBUS Optical Bus Terminal (OBT) (6GK1 500-3AA00) without an integrated
fiber-optic cable interface (e.g. programming devices (PGs) or operator panels
(OPs), see Figure 5-3).
The programming device/PC is connected to the RS 485 interface of the OBT by
means of the PROFIBUS cable. The OBT is integrated in the optical
PROFIBUS-DP line by means of its fiber-optic cable interface.
5-26
www.gkbpx.com
ET 200M with
IM 153-2 FO
Distances between 2 nodes:
Plastic fiber-optic cable up
to 50 m
PCF fiber-optic cable up to
300 m
Optical PROFIBUS-DP
S7-400 and M7-400 Programmable Controllers, Installation Manual
Other field devices without
fiber-optic cable interface
OBT
Other
nodes
C79000-G7076-C424-01