
3.2 Star topology
13
3 Network Topologies
Version 1.0 8/00
Fig. 4: Network structure in a redundant optical ring topology
RS 485 bus line
Optical fiber
Terminal unit /
bus segment
OLM/P1
2
OLM/G1
2
(-1300)
CH 1
CH 3
T
R
CH 2
T
R
Terminal unit /
bus segment
OLM/P1
2
OLM/G1
2
(-1300)
CH 1
CH 3
T
R
CH 2
T
R
Terminal unit /
bus segment
OLM/P1
2
OLM/G1
2
(-1300)
CH 1
CH 3
T
R
CH 2
T
R
Terminal unit /
bus segment
OLM/P1
2
OLM/G1
2
(-1300)
CH 1
CH 3
T
R
CH 2
T
R
3.3 Redundant optical ring
Switch on the terminating resistors in the bus port connectors (see 4.4.3, ”Connecting the electric RS 485 bus
lines“, p. 22) at both ends of the electrical star segment.
Do not connect a bus subscriber to the electrical star segment wherever possible.
Modules with one or two optical ports can be used to create an active PROFIBUS star coupler. Modules with one
optical port are sufficient for connecting a terminal or an RS 485 bus segment to the active star coupler.
If the link monitoring on the optical ports is activated, the fiber optic links are monitored by the respectively connected
OLM.
Note:
Optical ports which are not assigned (for instance, because they are reserved for a future system extension) indicate
a fiber break if the link monitoring is activated.
You can prevent this error report from being issued by activating the operating mode ”Line without fiber link monito-
ring “ at the non-assigned ports.
Please note that optical ports which are not connected must always be fitted with protective caps to guard against
extraneous light and dirt.
Summary of Contents for SIMATIC NET PROFIBUS
Page 10: ...Contents viii PROFIBUS Networks SIMATIC NET 6GK1970 5CA20 0AA1 Release 2 05 2000 ...
Page 11: ...PROFIBUS NETWORKS 1 ...
Page 26: ...PROFIBUS NETWORKS 1 16 PROFIBUS Networks SIMATIC NET 6GK1970 5CA20 0AA1 Release 2 05 2000 ...
Page 241: ...A 1 PROFIBUS Networks SIMATIC NET 6GK1970 5CA20 0AA1 Release 2 05 2000 Testing PROFIBUS A ...
Page 254: ...Testing PROFIBUS A 14 PROFIBUS Networks SIMATIC NET 6GK1970 5CA20 0AA1 Release 2 05 2000 ...
Page 288: ...Installing LAN Cables C 26 PROFIBUS Networks SIMATIC NET 6GK1970 5CA20 0AA1 Release 2 05 2000 ...
Page 325: ...F 1 PROFIBUS Networks SIMATIC NET 6GK1970 5CA20 0AA1 Release 2 05 2000 Dimension Drawings F ...
Page 338: ...Dimension Drawings F 14 PROFIBUS Networks SIMATIC NET 6GK1970 5CA20 0AA1 Release 2 05 2000 ...
Page 396: ...Infrared Link Modul ILM 6ZB530 3AC30 0BA1 54 Copyright by Siemens ...
Page 434: ......
Page 438: ...Contents ii PROFIBUS Optical Bus Terminal OBT C79000 G8976 C122 02 Contents ...
Page 450: ...Network Topology 4 4 PROFIBUS Optical Bus Terminal OBT C79000 G8976 C122 02 ...
Page 458: ...Installation and Startup 5 8 PROFIBUS Optical Bus Terminal OBT C79000 G8976 C122 02 ...
Page 460: ...Troubleshooting 6 2 PROFIBUS Optical Bus Terminal OBT C79000 G8976 C122 02 ...
Page 464: ...Technical Specifications 7 4 PROFIBUS Optical Bus Terminal OBT C79000 G8976 C122 02 ...
Page 468: ...References 9 2 PROFIBUS Optical Bus Terminal OBT C79000 G8976 C122 02 ...
Page 470: ...Abbreviations 10 2 PROFIBUS Optical Bus Terminal OBT C79000 G8976 C122 02 ...
Page 478: ...References I 4 PROFIBUS Networks SIMATIC NET 6GK1970 5CA20 0AA1 Release 2 05 2000 ...
Page 488: ...Glossary Glossary 8 PROFIBUS Networks SIMATIC NET 6GK1970 5CA20 0AA1 Release 2 05 2000 ...