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5v supply by CPU

Created by: Osld13 at: 2/12/2013 8:37 AM (8 Replies)

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2/12/2013 8:37 AM	Rate (0)
Osld13 Experienced Member Joined: 3/20/2012 Last visit: 1/9/2025 Posts: 118 Rating: (1)	Hi everybody, I'm looking for the current delivered by the 5v power supply on S7-300 CPUS. Where could i find this caracteristic? Thanks all.

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2/12/2013 9:14 AM	Rate (0)
umencho Diamond Member Joined: 3/21/2006 Last visit: 1/14/2025 Posts: 10239 Rating: (1182)	Would clarify a little bit deeply the issue? Best regards, Hristo Mihalev

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2/12/2013 2:10 PM	Rate (0)
Osld13 Experienced Member Joined: 3/20/2012 Last visit: 1/9/2025 Posts: 118 Rating: (1)	Hi Umencho, Each S7-300 card needs some 5v supply. For example the CP341's consumption is 70ma on the 5v supply delivered by the CPU.So how many CP341 could i supply with my CPU (315-2PN-DP)? Although, behind an IM361, the cards will be supplied by its 5v Power supply. So How many CP341 could i supply with my IM361? Thanks.

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2/12/2013 2:42 PM	Rate (0)
umencho Diamond Member Joined: 3/21/2006 Last visit: 1/14/2025 Posts: 10239 Rating: (1182)	Maximum number of centrally slottable CP 340s What can you do when the power requirement of the modules in the subrack exceeds the power supply provided by the CPU on the backplane bus? Best regards, Hristo Mihalev

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2/12/2013 3:27 PM	Rate (0)
Osld13 Experienced Member Joined: 3/20/2012 Last visit: 1/9/2025 Posts: 118 Rating: (1)	Thanks a lot Umencho. So all the CPU have the same 5v power supply (1,2A) . Then i understand that only 5 CP340 can be slot on the central backplane. But what about the CP341? It is already supplied by an external 24v. So it only needs 70ma on the 5v backplane. Then i don't understand why i can't slot more than 5 CP341 on the central backplane! Could it be a "bug" of the "Simatic selection tool"? Or is there another reason? Best regards.

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2/12/2013 4:59 PM	Rate (0)
umencho Diamond Member Joined: 3/21/2006 Last visit: 1/14/2025 Posts: 10239 Rating: (1182)	Did you try to add more CP in Hardware Configuration? And also the same with different CPUs. Basically theoretically there is no limitation of numbers of CP341 butpractical limits (memory, processing time, etc all dependant on the CPU). Best regards, Hristo Mihalev

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2/12/2013 5:52 PM	Rate (0)
Osld13 Experienced Member Joined: 3/20/2012 Last visit: 1/9/2025 Posts: 118 Rating: (1)	Thanks Umencho, I've obtained this limitation in "Simatic selection tool" (configurator). I haven't tried it yet in HW Config. I'm quite shure that HW Config won't verify everything,for example 5v Consumption! My project needs to slot 11 CP341 (may be in multiracks). I also wantto try to slot 11 "1SI" (6ES7 138-4DF11) behind an IM151-8 (not very optimistic!). Do you agree? (I'm already afraid of your answer!). Best regards Umencho.

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2/12/2013 6:31 PM	Rate (0)
umencho Diamond Member Joined: 3/21/2006 Last visit: 1/14/2025 Posts: 10239 Rating: (1182)	What kind of protocol CP341s will be? Trust to Hardware Configuration!
	Last edited by: UMENCHO at: 2/12/2013 6:31 PM
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2/14/2013 11:33 AM	Rate (0)
Osld13 Experienced Member Joined: 3/20/2012 Last visit: 1/9/2025 Posts: 118 Rating: (1)	Hi Umencho, "What kind of protocol CP341s will be?" 8CP341 will work in ASCII specific protocol, and 3 will work in Modbus RTU protocol. "Trust to Hardware Configuration! " I don't agree with your HW Conf trustiness! Its role is only to verify configurations in regard to logicals specifications. It has nothing to do with electricals specifications. I've tried to slot 8 CP340s in the central slot, it's ok!!! I can put 1 more backplane with an IM365 and even slot in it 8 CP340s, and it's ok!!! If you read the electrical specifications, it won't work! So when HW Config accepts 8 CP341s in the central backplane and 3 in the extend backplane, i'm not so confident... What do you think about 11 "SI" (6ES7 138-4DF11) behind an IM151-8? Thanks for your help. Best regards.

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