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| 10/17/2012 10:39 PM | |
Joined: 9/27/2006 Last visit: 10/14/2024 Posts: 12287 Rating:
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Hello saeed; Don,t be insulted if I say there is no problem; the system operates the way it was designed. Maybe not the way you would like it to operate, but there is a workaround. When you create a DB, you have a column called Initial values, that you may fill up or leave unchanged. Then when you run your program, you write values to the DB that are generated by the program, known asActual values. Unfortunately, the values that are retained by the DB are the Initial values... If you left them at zero, that is what is retained, that is what you see when you restart the PLC. So, if you want to retain values that correspond to your Actual values, you have to copy them into the Initial values column of the DB. Here is the easiest way I know to do so: How can you back up the actual values of DBs and markers? Note that when you restart the PLC the values now in Initial Values will be the ones saved at that time, not the last ones used by the DB. Hope this helps, Daniel Chartier |
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| 10/18/2012 1:43 AM | |
Joined: 10/7/2005 Last visit: 10/14/2024 Posts: 3024 Rating:
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Hello saeedplc
Correct.
Can't say for sure but please check Retentivity behavior of S7-300 CPU 31x and complete devices C7-6xx with MMC for more on this and note specifically the following info in it: DB's: - If the "Non-Retain" property of the data block is enabled, the data block is non-retentive. - When you create a DB with SFC 82, in the DB's attributes it is defined in Bit 2 whether the DB is to be retentive or not. With certain CPUs only part of the main memory can be used for retentive DBs. If the main memory for retentive data blocks is already full, then: No more DBs are created by SFC 82 "CREA-DBL". The error code W#16#80B2 (insufficient main memory) is returned via RET_VAL. Information on how much main memory can be used for retentive data blocks in your CPU is available in the manual "S7-300 CPU 31xC and CPU 31x, Technical Data", Entry ID: 12996906, in chapters 6 and 7. Memory Bytes: You can configure the retentive address areas of markers, S7 timers and S7 counters in the CPU properties from HW Config. The marker, S7 timer and S7 counter address areas retain their values if they have been defined as retentive. Otherwise they lose their values and are initialized with "0". Last but not least: 1.) Check what's happening in OB100, perhaps there is an "initialisation routine" that writeszero values to your DB's and/or Memory Bytesupon PLC restart. 2.) Could be a firmware issue, check Operating System Updates for CPU 315-2DPfor the latest one. I hope this helps |
Last edited by: fritz at: 10/18/2012 1:51 AMAdded "Last but not least" Cheers |
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| 10/19/2012 1:41 AM | |
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Joined: 10/7/2005 Last visit: 10/14/2024 Posts: 3024 Rating:
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Hello saeedplc I'm confused too now. You say you have an 6ES7315-2AG10-0AB0 CPU. If so, it does have an MMC and all DB's are retentive by default and you can NOT configure retentive DB's in the CPU properties (it is greyed out and not needed). Please read my previous entry and the link in it again to see what could be the cause for your DB's to behave non-retentively. If all fails, please upload your programhere for evaluation. One last thing to avoid further confusion: The retentive memory bytes area is configured in the 315-2AG10 CPU properties and needs to be set to suit your application. I hope this helps |
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Cheers |
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| 10/20/2012 1:21 AM | |
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Joined: 10/7/2005 Last visit: 10/14/2024 Posts: 3024 Rating:
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Hello saeedplc allow me to ask you again to provide answers for the following as it is extremely hard to help you without getting these kind of details (and please read my initial entry again and go through the links proivided in it): 1.) Do your DB's have the "Non-Retain" property set? 2.)What is happening in OB100? 3.) Have you tried the latest firmware? 4.) Upload your S7 program if none of the above helps |
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Cheers |
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| 4/2/2014 7:28 PM | |
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Posts: 7 Rating:
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Hi saeed, How you solve this problem, please explain...
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| 3/13/2015 11:14 AM | |
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Posts: 2 Rating:
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Unfortunately, I cannot now open the link above. Can someone give me some other link where I can see the explanation of procedure? Thank you in advance! |
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