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Profibus Line Topology with several s7-317 CPU

Created by: j_d at: 4/22/2009 9:55 AM (4 Replies)

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4/22/2009 9:55 AM	Rate (0)
j_d Posts: 2 Rating: (0)	Simple Question: How do I establish communication between several CPU S7-317-2DP using Profibus cable? Is it just to connect a cable from one CPU to the next, with the one in in the middle having to cables (in /out) through the plug? Is there anyconfigurations that must be done on the Profibus plugs?
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4/22/2009 10:47 AM	Rate (0)
j_d Posts: 2 Rating: (0)	I forgot to mention that I use electrical wiring, not optical fiber. Will the connector i that go in to the cpu that lies between two CPUs be connected as the picture shows? Attachment PROFIBUS plug.JPG (157 Downloads)
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4/22/2009 4:19 PM	Rate (0)
Sydney Gold Member Joined: 1/4/2008 Last visit: 1/4/2025 Posts: 703 Rating: (96)	Hello, communication and connection are two different terms... The connection in line topology could be as simple as you wrote, just interconnect all the nodes with the cable, it should go from the master to input connector part and the ouptput to another node and so on inone direction. Only you have to observe the rules about the node-node minimal(0,5m)and segment maximal(depends on the bitrate) cable length and the number of the nodes on the segment. Also on both ends have to be termination switched-on (or termination resistor inserted). Regards Sydney

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5/26/2009 7:23 AM	Rate (0)
how come Posts: 382 Rating: (47)	Dear j_d, Sydney was right! Just to add on that a proper termination from one node to anotheris also very important. I have attach a pdf file withinformationof a proper termination. Hope this helps! with regards, how come? Attachment Profibus Connector [6ES7 972-0BA41-0XA0].pdf (177 Downloads)
how come Posts: 382 Rating: (47)
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5/26/2009 8:57 AM	Rate (0)
dchartier Grandmaster-Expert Joined: 9/27/2006 Last visit: 1/25/2025 Posts: 12330 Rating: (2702)	Hello j_d; Now that Sidney and how come? have given you good information on the connections for Profibus-DP, how do you plan to establish communications between the CPUs? If you are using the integrated Profibus-DP interface on the CPUs, your only choice would be to setup one of them as a Profibus master, all the others as Profibus slaves, andconfigure a maximum of 244 bytes IN/244 bytes OUT for each slave CPU. The following link will show you how 2 CPUs can be setup as Profibus master and slave (the master here is a S7-400, but the priciples are the same): http://support.automation.siemens.com/WW/view/en/6518822 If you would prefer exchanging data peer-to-peer between the CPUs over Profibus-DP, then you cannot use the integrated DP ports, you must add a CP 342-5 communication processor to each rack. Here is an application note explaining how to connect and which functions you can use for this: http://support.automation.siemens.com/WW/view/en/20987358 Hope this helps, Daniel Chartier

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