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MEMORY CONCEPT DOUBT

Created by: vipz at: 8/17/2013 11:50 AM (35 Replies)

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8/17/2013 11:50 AM	Rate (0)
vipz Gold Member Joined: 9/2/2012 Last visit: 8/15/2024 Posts: 711 Rating: (30)	Dear All, In S7 300, while downloading it will get downloaded in to MMC card. In the case of retentive memory values, where it will get save?? in MMC or any other arrangement is in PLC ? In the case of S7 400, we can use RAM card or FLASH card. vRRAM card While downloading, program will get download in to plc internal memory, when it is full it will store in to RAM card. In this case also, where the retentive area located? Inside MMC or any other way? FLASH card While downloading, program will get download in to plc internal memory, Download to MMC require downloading in to card (by keeping CPU in STOP mode). In this case also, where the retentive area located? Inside MMC or any other way? · If my program size is greater than internal memory of CPU and not using any card; part of the program only will get download. If inserting RAM card, full download will take place with normal download button. · If my program size is greater than internal memory of CPU, am using FLASH card. And using normal download option, will it get download properly? In the case of backup batteries(400 system), is it giving backup supply to PLC Internal memory also ( I mean to both the RAM card and PLC internal mem) ? regards VIPZ
	Last edited by: vipz at: 8/17/2013 7:58 PM added Doubt related Batteries With Best Regards VIPZ
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8/22/2013 12:15 PM

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vipz

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Hai All,

i read the faq under

Entry ID:23596519. but still my doubts are not solved, anybody can help..

regards

vipz

With Best Regards

VIPZ

8/22/2013 12:41 PM	Rate (0)
Marcjan Platinum Member Joined: 4/22/2010 Last visit: 5/3/2024 Posts: 5697 Rating: (715)	Hello,. Please don't mix up MMC (for 300 CPU) and Flash/Ram- cards. How can I get an overview of the S7-400 memory concept? This FAQ, will answer most of your questions, if still in doubt about any part of this FAQ, please return. Regards, Marcjan
	Problem solved? Please let us know! Please no technical questions by PM, use the forum sections for your questions.
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8/22/2013 1:49 PM	Rate (1)
manmeet Gold Member Joined: 1/3/2006 Last visit: 2/19/2024 Posts: 726 Rating: (71)	Dear All, In S7 300, while downloading it will get downloaded in to MMC card. Yes In the case of retentive memory values, where it will get save?? in MMC or any other arrangement is in PLC ? MMC In the case of S7 400, we can use RAM card or FLASH card. Yes vRRAM card While downloading, program will get download in to plc internal memory, when it is full it will store in to RAM card. In this case also, where the retentive area located? Inside MMC or any other way? You don't hace access to PLC internal memory (Working memory). You have access to only Load memory. So everything is stored in Load Memory. Work memory can't be increased where as Load memory can be increased using (MMC, RAM, EPROM) In 400 there are two kinds of Load Memory RAM EPROM (Flash Card) There is no MMC here ! In a given 400 system you can either use RAM or EPROM in a given slot of CPU. If RAM is used no special method required to save program but in case of EPROM you have to choose "Load user program to memory card" option. RAM needs battery to save your program while EPROM does not requires it. Always think Load Memory as hard disk of your PC, and Work Memory as RAM of PC. Programs are saved in Hard Drive (Load Memory) and OS decide how much of RAM (Work Memory) is to be alloted when it is made to run. Now if you program is so big that it required more RAM(Work Memory) then installed capacity, you have to buy a PC (PLC) with more RAM (Work Memory) ! Simple ! Regards, Manmeet.
	Last edited by: manmeet at: 8/22/2013 1:54 PM
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8/22/2013 6:31 PM	Rate (0)
vipz Gold Member Joined: 9/2/2012 Last visit: 8/15/2024 Posts: 711 Rating: (30)	Dear Manmeet, thank you for the reply.. I agree.. regarding, ·If my program size is greater than internal memory of CPU, am using FLASH card. And using normal download option, will it get download properly? ?? In the case of backup batteries(400 system), is it giving backup supply to PLC Internal memory also ( I mean to both the RAM card and PLC internal mem) ? ?? regards vipz
	With Best Regards VIPZ
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8/22/2013 6:59 PM	Rate (0)
Marcjan Platinum Member Joined: 4/22/2010 Last visit: 5/3/2024 Posts: 5697 Rating: (715)	Hello, 1st : if the program is bigger than the load memory it will not be downloaded correctly. 2nd: yes battery supplies both cpu ram and external ram-card. Regards, Marcjan
	Problem solved? Please let us know! Please no technical questions by PM, use the forum sections for your questions.
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8/22/2013 7:10 PM	Rate (0)
vipz Gold Member Joined: 9/2/2012 Last visit: 8/15/2024 Posts: 711 Rating: (30)	Dear Both, in s7 400 also, retentive memory is inside RAM/FLASH card ?? in s7 400, we can use plc without LOAD MEMORY (WITHOUT RAM,FLASH CARD) provided program size is small . correct ? in that case retentivity will work if am providing buffer battery ?? regards vipz
	With Best Regards VIPZ
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8/23/2013 6:10 AM	Rate (0)
manmeet Gold Member Joined: 1/3/2006 Last visit: 2/19/2024 Posts: 726 Rating: (71)	in s7 400 also, retentive memory is inside RAM/FLASH card ?? Yes in s7 400, we can use plc without LOAD MEMORY (WITHOUT RAM,FLASH CARD) provided program size is small . correct ? Your prgram goes in Load Memory and you need it for any downloaing to take place. You can just do some configuration changes in hardware to optimize the usage of work memory. in that case retentivity will work if am providing buffer battery ?? Yes Also follwong are few lines which I have taken from Simatic Manager Help. Just copy paste "Retentive Memory Areas on S7-400 CPUs" for more details. Without battery backup, only a restart (warm restart) is possible and there are no retentive memory areas. You can declare a certain number of memory bits, timers, and counters as retentive (the number depends on your CPU). During a restart (warm restart) when you are using a backup battery, this data is also retained. Regards Manmeet
	Last edited by: manmeet at: 8/23/2013 6:11 AM
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8/23/2013 7:21 AM	Rate (0)
vipz Gold Member Joined: 9/2/2012 Last visit: 8/15/2024 Posts: 711 Rating: (30)	Deat Manmeet, some points are not clear to me.. 1. in s7 400 can we use PLC without any load memory?? consider my test program is very small compared to plc memory. 2. if am using plc without load memory, but providing buffer battery, retentivity will happen ?? 3. if am using FLASH card without battery backup, retentivity will work ?? regards vipz
	With Best Regards VIPZ
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8/23/2013 7:42 AM	Rate (1)
Marcjan Platinum Member Joined: 4/22/2010 Last visit: 5/3/2024 Posts: 5697 Rating: (715)	Hello, 1. Load memory of the 400 system is the Internal Ram or External Ramcard/Flash, picture From the load memory the programblocks are loaded into the (internal) Work memory. 2. yes if you have backup battery the Retentivity will last as long as your battery is o.k.. 3. No. after power on the program is loaded from flash to work memory, all data blocks will use initial values. Without battery the work memory and the internal Ram is cleared. Regards, Marcjan
	Last edited by: Marcjan at: 8/23/2013 7:43 AM Problem solved? Please let us know! Please no technical questions by PM, use the forum sections for your questions.
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