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S7 317-2DP not retaining DB status on power off/on

4/19/2008 7:42 PM	Rate (0)
Dr J Posts: 2 Rating: (0)	I have a 317 2DP processor with a 2MB MMC installed, program runs ok, but when I power off and on all data in my DBs is lost (all registers set to zero). I have not used the non-retain parameter or written any code to reset this data and so I cannot understand what the problem could be - anyone got any tips ?
Dr J Posts: 2 Rating: (0)
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4/19/2008 10:00 PM	Rate (0)
Late Platinum Member Joined: 1/7/2006 Last visit: 5/11/2025 Posts: 2705 Rating: (321)	Dr J I have a 317 2DP processor with a 2MB MMC installed, program runs ok, but when I power off and on all data in my DBs is lost (all registers set to zero). I have not used the non-retain parameter or written any code to reset this data and so I cannot understand what the problem could be - anyone got any tips ? Hi, Which Firmware version is the CPU 317-2DP ? It could be that when it is not the newest version that that is the problem... It could also be that the MMC is not good, which type is it (00/01/11/20) ?
	I hope that the answer will help, if you have still questions, don't hesitate to ask me. All the best, Late Never say never, think in solutions, not in trouble......
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4/21/2008 4:45 PM	Rate (0)
Wizard Diamond Expert Joined: 4/24/2006 Last visit: 1/14/2026 Posts: 9105 Rating: (1204)	Dear Dr J, Please have a look at this faq: http://support.automation.siemens.com/WW/view/en/598803 And read manual: http://support.automation.siemens.com/WW/view/en/12996906 Look at memory concept. A CPU317-2DP can only 256 kByte of retentive data. Best regards, Wizard

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5/12/2008 2:18 AM	Rate (0)
pici_c Posts: 80 Rating: (2)	Hi! I have CPU 313C-2 DP. I know that it has 256B retentive memory in M area. I use a 128KB MMC. I use several instance DBs in my program. I experienced, that sometimes after Power OFF, the datas in DBs are lost, but sometimes are not. I store about 3KB data in them, and they are important. What are the causes when I lost them? (I couldn'r figure it out). DB-s are stored on the MMC and they should save data, aren't they? And the amount restriction is only the size of the MMC, isn't it? thanks pici_C
pici_c Posts: 80 Rating: (2)
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1/29/2011 8:07 AM	Rate (0)
KayBee Posts: 241 Rating: (7)	Hi, I found this , may be helpful to you. " Retentive data in the main memory The contents of retentive DBs are always retentive at restart and POWER ON/OFF. Retentive data blocks can be uploaded to the main memory in accordance with the maximum limit allowed by the main memory. In the case of CPU versions V2.0.12 and higher, non-retentive DBs are also supported. Non-retentive DBs are initialized from the load memory with their initial values at restart or POWER ON/OFF. Non-retentive data blocks and code blocks can be loaded in accordance with the maximum main memory limit. The size of the retentive main memory (for retentive data blocks) of the CPU can be found in the chapters "Technical specifications of CPU 31x (Page 239)" and "Technical specifications of CPU 31xC (Page 183)"."
KayBee Posts: 241 Rating: (7)
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