
PROFIBUS NETWORKS
1-9
PROFIBUS Networks SIMATIC NET
6GK1970-5CA20-0AA1 Release 2 05/2000
Active and Passive Nodes
The access technique is not dependent on the transmission medium. Figure 1-1
“Principle of the PROFIBUS Medium Access Technique” shows the hybrid
technique with active and passive nodes. This is explained briefly below:
S
All active nodes (masters) form the logical token ring in a fixed order and each
active node knows the other active nodes and their order in the logical ring (the
order does not depend on the topological arrangement of the active nodes on
the bus).
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The right to access the medium, the “Token”, is passed from active node to
active node in the order of the logical ring.
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If a node has received the token (addressed to it), it can send frames. The time
in which it is allowed to send frames is specified by the token holding time.
Once this has expired, the node is only allowed to send one high priority
message. If the node does not have a message to send, it passes the token
directly to the next node in the logical ring. The token timers from which the
maximum token holding time is calculated are configured for all active nodes.
S
If an active node has the token and if it has connections configured to passive
nodes (master-slave connections), the passive nodes are polled (for example
values read out) or data is sent to the slaves (for example setpoints).
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Passive nodes never receive the token.
This access technique allows nodes to enter or leave the ring during operation.
1.2.3
Transmission Techniques
The physical transmission techniques used depend on the SIMATIC NET
PROFIBUS transmission medium:
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RS-485 for electrical networks on shielded, twisted pair cables
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Optical techniques according to the PROFIBUS User Organization guideline /3/
on fiber-optic cables
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Wireless techniques based on infrared radiation
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IEC 61158-2 technique for intrinsically safe and non-intrinsically safe electrical
networks in process control (PROFIBUS-PA) based on shielded, twisted pair
cables.
Содержание SIMATIC NET PROFIBUS
Страница 10: ...Contents viii PROFIBUS Networks SIMATIC NET 6GK1970 5CA20 0AA1 Release 2 05 2000 ...
Страница 11: ...PROFIBUS NETWORKS 1 ...
Страница 26: ...PROFIBUS NETWORKS 1 16 PROFIBUS Networks SIMATIC NET 6GK1970 5CA20 0AA1 Release 2 05 2000 ...
Страница 167: ...5 1 PROFIBUS Networks SIMATIC NET 6GK1970 5CA20 0AA1 Release 2 05 2000 Active Components for RS 485 Networks 5 ...
Страница 184: ...Active Components for RS 485 Networks 5 18 PROFIBUS Networks SIMATIC NET 6GK1970 5CA20 0AA1 Release 2 05 2000 ...
Страница 185: ...6 1 PROFIBUS Networks SIMATIC NET 6GK1970 5CA20 0AA1 Release 2 05 2000 Passive Components for PROFIBUS PA 6 ...
Страница 197: ...7 1 PROFIBUS Networks SIMATIC NET 6GK1970 5CA20 0AA1 Release 2 05 2000 Passive Components for Electrical Networks 7 ...
Страница 228: ...Passive Components for Electrical Networks 7 32 PROFIBUS Networks SIMATIC NET 6GK1970 5CA20 0AA1 Release 2 05 2000 ...
Страница 229: ...8 1 PROFIBUS Networks SIMATIC NET 6GK1970 5CA20 0AA1 Release 2 05 2000 Active Components for Optical Networks 8 ...
Страница 236: ...Active Components for Optical Networks 8 8 PROFIBUS Networks SIMATIC NET 6GK1970 5CA20 0AA1 Release 2 05 2000 ...
Страница 237: ...9 1 PROFIBUS Networks SIMATIC NET 6GK1970 5CA20 0AA1 Release 2 05 2000 Active Components for Wireless Networks 9 ...
Страница 240: ...Active Components for Wireless Networks 9 4 PROFIBUS Networks SIMATIC NET 6GK1970 5CA20 0AA1 Release 2 05 2000 ...
Страница 241: ...A 1 PROFIBUS Networks SIMATIC NET 6GK1970 5CA20 0AA1 Release 2 05 2000 Testing PROFIBUS A ...
Страница 254: ...Testing PROFIBUS A 14 PROFIBUS Networks SIMATIC NET 6GK1970 5CA20 0AA1 Release 2 05 2000 ...
Страница 263: ...C 1 PROFIBUS Networks SIMATIC NET 6GK1970 5CA20 0AA1 Release 2 05 2000 Installing LAN Cables C ...
Страница 288: ...Installing LAN Cables C 26 PROFIBUS Networks SIMATIC NET 6GK1970 5CA20 0AA1 Release 2 05 2000 ...
Страница 290: ...Installation Instructions for SIMATIC NET D 2 PROFIBUS Networks SIMATIC NET 6GK1970 5CA20 0AA1 Release 2 05 2000 ...
Страница 325: ...F 1 PROFIBUS Networks SIMATIC NET 6GK1970 5CA20 0AA1 Release 2 05 2000 Dimension Drawings F ...
Страница 338: ...Dimension Drawings F 14 PROFIBUS Networks SIMATIC NET 6GK1970 5CA20 0AA1 Release 2 05 2000 ...
Страница 339: ...G 1 PROFIBUS Networks SIMATIC NET 6GK1970 5CA20 0AA1 Release 2 05 2000 Operating Instructions ILM OLM OBT G ...
Страница 340: ...Operating Instructions ILM OLM OBT G 2 PROFIBUS Networks SIMATIC NET 6GK1970 5CA20 0AA1 Release 2 05 2000 ...
Страница 396: ...Infrared Link Modul ILM 6ZB530 3AC30 0BA1 54 Copyright by Siemens ...
Страница 434: ......
Страница 438: ...Contents ii PROFIBUS Optical Bus Terminal OBT C79000 G8976 C122 02 Contents ...
Страница 442: ...The SIMATIC NET PROFIBUS OBT Product 2 2 PROFIBUS Optical Bus Terminal OBT C79000 G8976 C122 02 ...
Страница 450: ...Network Topology 4 4 PROFIBUS Optical Bus Terminal OBT C79000 G8976 C122 02 ...
Страница 458: ...Installation and Startup 5 8 PROFIBUS Optical Bus Terminal OBT C79000 G8976 C122 02 ...
Страница 460: ...Troubleshooting 6 2 PROFIBUS Optical Bus Terminal OBT C79000 G8976 C122 02 ...
Страница 464: ...Technical Specifications 7 4 PROFIBUS Optical Bus Terminal OBT C79000 G8976 C122 02 ...
Страница 468: ...References 9 2 PROFIBUS Optical Bus Terminal OBT C79000 G8976 C122 02 ...
Страница 470: ...Abbreviations 10 2 PROFIBUS Optical Bus Terminal OBT C79000 G8976 C122 02 ...
Страница 478: ...References I 4 PROFIBUS Networks SIMATIC NET 6GK1970 5CA20 0AA1 Release 2 05 2000 ...
Страница 488: ...Glossary Glossary 8 PROFIBUS Networks SIMATIC NET 6GK1970 5CA20 0AA1 Release 2 05 2000 ...