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| 8/16/2013 12:00 PM | |
Joined: 1/21/2013 Last visit: 11/20/2024 Posts: 4620 Rating:
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Hi iwanhoo, what type of PLC do you have? |
| 8/16/2013 12:18 PM | |
Joined: 1/26/2012 Last visit: 9/30/2021 Posts: 27 Rating:
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PLC should be S7-300. |
| 8/16/2013 2:25 PM | |
Joined: 9/27/2006 Last visit: 3/20/2025 Posts: 12344 Rating:
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Hello iwanhoo; The following document describes communication functions between CPUs very well: CPU-CPU communication with SIMATIC controllers (compendium) I have extracted a page on MPI caracteristicsfrom the compendium, the the attachment below. Notice it states that MPI can support up to 126 partners, which is true if repeaters are integrated to extend thesegment length and number of partners. A basic RS-485 network segment for MPI extends a maximum of 50 m at 187,5 kb, because the MPI ports are non-isolated. It can hold a maximum of 32 nodes, addresses from 0 to 31. If you want to add more participants or extend the length of the network, you have to add a RS-485 repeater evey 50 m or everytime you add another 31 nodes (the repater is considered a node). This becomes expensive very fast, and since the speed is limited, quickly becomes very slow (every node is a master that requests the token to exchange data, the more participants the slower the token rotation time).. So it is recommended to use a single segment for MPI, 187,5 kb, 50 m, with a maximum of 32 nodes in all. Hope this helps, Daniel Chartier |
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