7/4/2009 2:37 PM | |
Joined: 10/7/2005 Last visit: 10/11/2024 Posts: 3024 Rating: (1054) |
Dear all I am a bit suprised by edr's assertion, especially hisstatement "the number of devices ona Profinetnetwork hasnearly noimpact on the achievable update timefor the device information". As far as I know, standard Profinet (i.e. without IRT and therequired use of expensive IRT capable hardware), is update time wise no better or worse than good old Profibus. There seems to be this "funny" perception out there that just because its Ethernet and runs at 100Mbit/s, it has to be "lightning fast". I'm afraid to say that this is not necessarily the case. Don't take my word for it though, have a look at thisPerformance calculator from Siemens and do your own comparisons ofa Profibus and Profinet I/O system (you'll be suprised how well Profibus holds up). Lastely, good luck Navnag with your project and your task to "convince the customer to eliminate OLMs altogether and have many more electrical Profibus segments with less no of devices per segment. We hope that he will agree". |
Last edited by: fritz at: 7/4/2009 4:20 PMCheers |
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This contribution was helpful to1 thankful Users |
7/7/2009 3:25 PM | |
Joined: 10/7/2005 Last visit: 10/11/2024 Posts: 3024 Rating: (1054) |
Hello Navnag If the customers requirements are in fact this simple (or shalI say silly), then why not offer him a simple(or shall I say silly) solution like this one: Construct a Fibre optic ring with OLM's and attach only ONE DP Slave per OLM RS485 port! You can have up to 127 OLM's in a ring which just exceeds the max number of DP Slaves you can have per Master segment. Voila, problem solved |
Last edited by: fritz at: 7/8/2009 12:37 AMI think I plagerised mumbles post wihtout realising it, he basically had already stated this when he wrote: "one is to firstly provide a (or many) redunant FO ring network(s) and then have each slave on its own segment." Last edited by: fritz at: 7/7/2009 3:41 PMCheers |
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7/7/2009 3:41 PM | |
Posts: 5822 Rating: (412)
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Dear fritz, I agree totally with you... but they want to get rid of these OLMs... anyway. I am clueless how to solve this otherwise. Best regards J_Bell |
8/4/2009 8:24 AM | |
Joined: 11/21/2007 Last visit: 9/25/2024 Posts: 2325 Rating: (308) |
Hi All How about the attached configuration ? Any Comments ? Regards Navnag AttachmentProfibus system_Schematic_02.pdf (296 Downloads) |
There is no such thing as the last bug in a program |
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8/4/2009 9:55 AM | |
Joined: 10/7/2005 Last visit: 10/11/2024 Posts: 3024 Rating: (1054) |
hello navnag I like your persistency, but am afraid to say that you can NOT do this (the OLM manual has this "silly" statement that says: "There must be no RS 485 bus line within the ring" ). |
Cheers |
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