Siemens Simatic S7-200 System Manual page 164

Network Communications and the S7-200 CPU
Cable for a PROFIBUS Network
Table 9-4 lists the general specifications for a PROFIBUS network cable. See Appendix G for
the Siemens order number for PROFIBUS cable meeting these requirements.
Table 9-4
Type
Conductor cross section
Cable capacitance
Nominal impedance
The maximum length of a PROFIBUS network segment depends on the baud rate and the
type of cable used. Table 9-5 lists the maximum segment lengths for cable matching the
specifications listed in Table 9-4.
Table 9-5
9.6 kbaud to 93.75 kbaud
3 Mbaud to 12 Mbaud
Network Repeaters
Siemens provides network repeaters to connect PROFIBUS network segments. See
Figure 9-4. The use of repeaters extends the overall network length and/or allows adding
devices to a network. PROFIBUS allows a maximum of 32 devices on a network segment of
up to 1,200 m (3,936 ft.) at 9600 baud. Each repeater allows you to add another 32 devices
to the network and extend the network another 1,200 m (3,936 ft.) at 9600 baud. Up to 9
repeaters may be used in a network. Each repeater provides bias and termination for the
network segment. See Appendix G for ordering information.
32 Devices/1,200 m (3,936 ft.)
Figure 9-4
9-8
General Specifications for a PROFIBUS Network Cable
General Features
Maximum Cable Length of a Segment in a PROFIBUS Network
Transmission Rate
187.5 kbaud
500 kbaud
1.5 Mbaud
Repeater
CPU CPU
Network with Repeaters
Specification
Shielded, twisted pair
2
24 AWG (0.22 mm ) or larger
< 60 pF/m
100 Ω to 120 Ω
Maximum Cable Length of a Segment
1,200 m (3,936 ft.)
1,000 m (3,280 ft.)
400 m (1,312 ft.)
200 m (656 ft.)
100 m (328 ft.)
Repeater
CPU CPU
32 Devices/1,200 m (3,936 ft.)
S7-200 Programmable Controller System Manual
C79000-G7076-C230-02