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S7-300 CPU 315-2 DP Redundancy & Limited Number of ET200M
Created by: A.Fawzy at: 12/14/2012 12:14 AM (5 Replies)
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| 12/14/2012 1:21 AM | |||||||||||||||||||||
Joined: 9/27/2006 Last visit: 9/16/2024 Posts: 12282 Rating:
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Hello A,Fawzy; Whenever you have such a query, go back to the basics. In this case, review the contents of the SWR manual: SIMATIC S7-300/S7-400 Software redundancy for SIMATIC S7 4.1 How does a system with software redundancy work? A system with software redundancy is characterized by: · Two S7-300 and/or S7-400 stations that are linked via bus system. · A redundant user program that is loaded on both stations. · Two DP master systems to which ET 200M distributed I/O devices with a redundant DP slave interface module such as the IM 153-2 are connected. · Integration of the blocks provided in the "Software redundancy" package Note that the mention of ET 200M distributed I/O devices is very general, and indicates no “one station” limit. Take the following information in Ch. 6.1 in consideration at the same time: Supported number of ET 200M DP slaves Depends on the CPU used (up to 64 ET 200M DP slaves are supported on CPU 414-2DP) Also note that the IM 153-2 limitation to 8 modules, I would like to point out that the latest IM 153-2HF modules can support up to 12 I/O modules on their rack: see the following link 6ES7153-2BA02-0XB0 You can also find the IM 153-2HF in a so-called Red-Bundle, so you recieve 2 IM 153-2HF modules with one IM/IM Active Bus module: You will still need the special rail suppport and Active Bus Modules for your I/O modules. See the following links:
Hope this helps,
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Last edited by: dchartier at: 12/14/2012 3:42 AMLast edited by: dchartier at: 12/14/2012 2:05 AMTo fritz: Not wanting to enter a self-congratulation society, but I hope our friend A.Fawzy is reassured that we both agree on the the solution to his problem... Cheers! |
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| 12/14/2012 1:56 AM | |
Joined: 10/7/2005 Last visit: 9/16/2024 Posts: 3020 Rating:
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Hello A.Fawzy you can certainly have more than one ET200M station on an S7-300 Software redundancy basedsystem. Chapter 6.5 of the SIMATIC S7-300/S7-400 Software redundancy for SIMATIC S7 manuallists the changeover times for up to 64 ET200M stations, but I assume you could in theory use up to124 ET200M stations (i.e. the limit of a an S7 based DP Master system and providing the CPU supports this and has the address space for it, see the technical spec of your 315 for more). Note too that 12 modules is now the limit for newer IM153-2 based ET200M stations. I suggest you start by studying the above linked manual carefully and also have a look at Which modules can you use when implementing software redundancy? should you choose to go down the road of Software redundancy. As a Software redundancy based solution has a fair few things to be aware of (you might call them limitations), you may alternatively consider using an S7-400H based system instead and the discussion in the thread software and hardware redundancy in siemensmay help you with the decision making. I hope this helps |
Last edited by: fritz at: 12/14/2012 1:58 AMneed to learn to type and link faster, Daniel beat me to the answer but at least we agree in our advice. Cheers |
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| 12/14/2012 8:11 AM | |
Joined: 5/28/2008 Last visit: 9/9/2024 Posts: 4515 Rating:
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Hello Mr. Fawzy, You are right that SW is a slower than S7-400H. For non critical applications which doesn't need immediate actions, it is acceptable to use SW redundancy. "Slower" & "Faster" terms reflects the switching time between master CPU & standby CPU in case of CPU faliure. In SW Redundancy, during switching, all outputs are freezed until standby CPU update the process image. But in Hardware Redundancy (S7-400H), the process image update works as if it was come from one CPU. Thus because what we call Hot-Stand by and synchronization between the two CPUs. Another point to add, You can reduce number of racks by using digital modules with 64 signals. DI 64/ DO 64. So, if you sucess to reduce one rack, your cost will be reduced by price of 2 IM 153-2 HF. Attached a valuable document that explains SW redundancy, S7-400H and options for redundant IOs as well. Hope this helps.
AttachmentSW red vs. S7-400H_en.pdf (298 Downloads) |
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Ayman Elotaify |
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| 12/15/2012 3:30 AM | |
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Posts: 9 Rating:
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Thank you a lot Mr.Ayman for the document |
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