Technical data

PROFIBUS Network Manual
System Manual, Edition 04/2009, C79000-G8976-C124-03
3
Table of contents
1 PROFIBUS networks................................................................................................................................. 9
1.1 Local area networks in manufacturing and process automation ...................................................9
1.1.1 General introduction.......................................................................................................................9
1.1.2 Overview of the SIMATIC NET system........................................................................................10
1.1.3 Bus systems for industrial use .....................................................................................................11
1.2 Basics of the PROFIBUS network ...............................................................................................15
1.2.1 Attachable systems......................................................................................................................15
1.2.2 Standards.....................................................................................................................................15
1.2.3 Access mechanism ......................................................................................................................16
1.2.4 Protocols for PROFIBUS .............................................................................................................17
1.2.5 Transmission mode......................................................................................................................19
1.2.5.1 Physical transmission techniques................................................................................................19
1.2.5.2 Transmission techniques according to EIA standard RS485 ......................................................19
1.2.5.3 Transmission techniques for optical components........................................................................21
1.2.5.4 Transmission techniques for PROFIBUS PA...............................................................................22
2 Topologies of SIMATIC NET PROFIBUS networks ................................................................................. 25
2.1 Topologies of RS485 networks....................................................................................................25
2.1.1 Overview ......................................................................................................................................25
2.1.2 Components for transmission speeds up to 1.5 Mbps ................................................................26
2.1.3 Components for transmission speeds up to 12 Mbps .................................................................27
2.2 Topologies of optical networks.....................................................................................................28
2.2.1 Electrical - optical gateway ..........................................................................................................28
2.2.2 Topology with integrated optical interfaces..................................................................................28
2.2.3 Topologies with OLMs .................................................................................................................29
2.2.4 Combination of integrated optical interfaces and OLMs..............................................................34
2.3 Topologies of wireless networks..................................................................................................35
2.4 Topologies with PROFIBUS PA...................................................................................................37
3 Network configuration.............................................................................................................................. 41
3.1 Configuring electrical networks....................................................................................................41
3.1.1 Overview ......................................................................................................................................41
3.1.2 Segments for transmission speeds up to a maximum of 500 kbps .............................................42
3.1.3 Segments for a transmission speed of 1.5 Mbps.........................................................................43
3.1.4 Segments for transmission speeds up to a maximum of 12 Mbps..............................................46
3.1.5 Configuring electrical networks with RS-485 repeaters...............................................................47
3.2 Configuring optical networks........................................................................................................48
3.2.1 Overview ......................................................................................................................................48
3.2.2 How a fiberoptic cable transmission system works .....................................................................48
3.2.3 Optical power budget of a fiberoptic transmission system ..........................................................50
3.2.4 Cable lengths for plastic and PCF FO links.................................................................................52
3.2.5 Calculating the signal loss on glass fiber-optic links with OLMs..................................................54
3.3 Frame transmission time..............................................................................................................58
3.3.1 Overview ......................................................................................................................................58
3.3.2 Configuring optical buses and star topologies with OLMs...........................................................59