10/16/2017 5:58 PM | |
Joined: 9/27/2006 Last visit: 5/9/2024 Posts: 12257 Rating: (2666)
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Hello ted; When you say you have a little bit knowledge about As-i, what do you mean exactly? In case you would like a refresher, here is a Siemens description of the basics of As-i: https://www.siemens.be/eit/microautomation/downloads/AS_Interface_EN.pdf Now, there are 2 formats of addressing in As-interface. The original specification allowed 31 slaves, with a cyclic loop of 5 ms max. The later specification allowed up to 62 slaves, with a cycle of 10 ms, The address space has not changed, however, it is limited to 16 bytes, so every slave is allowed 4 bits. See the extract below from the Siemens CP 342-2 Asi master addressing scheme. In this table, you can notice that slaves addressed with the original scheme are marked 1 to 31, the slaves addressed with the extended addressing are marked 1A to 31A. With extended addressing, the As-i master interrogates slaves 1-31 first, then slaves 1A to 31A. That way. with the same address space you can read/write to 62 slaves on the bus. You generally need an external hand-held programmer to attribute an address to an As-i slave; some masters will allow programming the address through software functions (the CP 342-2 does so, see the manual above). Hope this helps, Daniel Chartier |
Last edited by: dchartier at: 10/16/2017 7:27:11 PM |
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10/16/2017 7:55 PM | |
Joined: 3/14/2017 Last visit: 2/11/2024 Posts: 100 Rating: (1) |
hello daniel a little bit means about definition of Asi but i don't know anything about Asi |
10/16/2017 8:01 PM | |
Joined: 3/14/2017 Last visit: 2/11/2024 Posts: 100 Rating: (1) |
hello daniel but what is the difference between Asi Bus and Asi Safety? |
10/16/2017 8:38 PM | |
Joined: 9/27/2006 Last visit: 5/9/2024 Posts: 12257 Rating: (2666)
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Hello ted; The developpers of As-i have integrated a Safety extension to the bus, integrating "Safety" (certified by TUV to SIL 3/PLe) messages to run Inside the As-i cycle, called ASIsafe. There is something similar for Profinet and Profibus, called ProfiSafe. In attachment you will find a description of ASIsafe, from the AS-i system manual: System Manual AS-Interface system ASIsafe - Industry Support Siemens Look at Chapter 8 for technical presentation of ASIsafe. And this product information page can also be informative: You need specialised masters or interfaces, Safety I/O modules for AS-i, and an additional As-i Safety Monitor to implement ASIsafe. AS-i and ASIsafe will run together on the same bus without interference if they are both configured correctly. Hope this helps, Daniel Chartier |
Last edited by: dchartier at: 10/16/2017 8:39:27 PM |
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