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Retain variable after update/download of datablock

Created by: ev200 at: 10/15/2013 2:42 PM (10 Replies)

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10/15/2013 2:42 PM	Rate (0)
ev200 Posts: 4 Rating: (0)	Hi, is there some way to retain variable from datablock after updating the same datablock in s7-1200? im using s7-1214c TIA Portal 11 SP2 and v12 whitout any luck, after updating datablock lets say with new variables, old variable marked as "Retain" gets set to zero in the manual it says "When you download one or more DBs from STEP 7 V11 to an S7-1200 V2 CPU, the retentive and non-retentive values of those DBs are set to their start values. The next transition to RUN performs a warm restart, setting all non-retentive data to their start values and setting all retentive data to their retained values. When you download project elements (such as device configuration, code blocks or DBs) from STEP 7 V10.5 to any S7-1200 CPU or from STEP 7 V11 to an S7-1200 V1 CPU (or a V2 CPU that has been configured as a V1 CPU), the next transition to RUN mode resets all of the DBs in the project to their start values." so im using STEP 7 V11 SP2 and S7-1200 V3 and still my retentive values get resets what im doing wrong? it was so easy on s7-200 to use retentive variables... Thanks
ev200 Posts: 4 Rating: (0)
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10/15/2013 2:58 PM	Rate (0)
Nelliyan randy Posts: 461 Rating: (29)	This link may help u Regards, Nelliyan.G
Nelliyan randy Posts: 461 Rating: (29)
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10/15/2013 3:49 PM	Rate (0)
ev200 Posts: 4 Rating: (0)	Thank you, but my variables are retentive already, when i switch off plc it retains the data the problem is when im working on the program and need to add new variable to some datablock then after download all other variables in the same datablock get value of zero
ev200 Posts: 4 Rating: (0)	Last edited by: ev200 at: 10/15/2013 3:50 PM
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10/15/2013 3:56 PM	Rate (0)
0_Einstein Diamond Expert Joined: 7/7/2010 Last visit: 10/15/2024 Posts: 15315 Rating: (2430)	ev200 Thank you, but my variables are retentive already, when i switch off plc it retains the data the problem is when im working on the program and need to add new variable to some datablock then after download all other variables in the same datablock get value of zero Take a snapshot of your DB before downloading, then restore your snapshot after the download - if the values change. There is a way to download and not select the overwrite option in V12. The overwrite means to override the current _values_ of the tags/DB tags with new values.
	science guy
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10/15/2013 4:33 PM	Rate (0)
ev200 Posts: 4 Rating: (0)	"There is a way to download and not select the overwrite option in V12. " Thanks i'll have to try that tomorrow hope it will work how can i take a snapshot of my DB btw? the problem is i add variables often and i like to store lots of data in DB, and it gets really annoying if i have to restore manualy like 20 variables every time...
ev200 Posts: 4 Rating: (0)
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10/15/2013 4:43 PM	Rate (1)
0_Einstein Diamond Expert Joined: 7/7/2010 Last visit: 10/15/2024 Posts: 15315 Rating: (2430)	ev200 "There is a way to download and not select the overwrite option in V12. " Thanks i'll have to try that tomorrow hope it will work how can i take a snapshot of my DB btw? the problem is i add variables often and i like to store lots of data in DB, and it gets really annoying if i have to restore manualy like 20 variables every time... In V12, do not overwrite the values and the original values _should_ be retained. However, just to be sure, setup a watch table with all values of concerns, monitor watch table, highlight watch table and save (snapshot). After downloading, go to watch table, and any values not what you want, paste values and click lightning bolt to update values per snapshot. Note, this is not the only way, but it is easy to understand and explain in the forums. If someone else has a nice procedure for taking the snapshot using V12 tools, please post.
	science guy
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This contribution was helpful to 1 thankful Users Nelliyan randy

10/15/2013 7:36 PM	Rate (0)
ev200 Posts: 4 Rating: (0)	yeah, i really really hope using v12 with your advice will solve this problem permanently, will try tomorrow for sure your advice is very helpful thank you
ev200 Posts: 4 Rating: (0)
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2/21/2014 12:05 PM	Rate (0)
HOWERLIN Posts: 25 Rating: (0)	Dear all, Have you find convinent solution for this topics? I use TIA V12 SP1 Update 3 , it is not working. In my previous projects, I use DB to structure my variable, and the problem is when I add or modified variable in DB and download to PLC , I need to stop CPU and lose all retain value in the DB. It's too inconvenient and infeasible when I want to write program offline. That's why I want to use memory area (M) with tags to program. Because when I modified M area, it is better that I don't need to stop PLC and will not lose value when download. I use tags to store data in memory, and memory is set as retained. When download a modified DB, all my retained memory is erase to zero. It's too unreasonable, modified a DB structure that will effect M area retainability. Is there a convinent way that we can easily modify data without snapshot or force-table, and don't need to stop PLC when download a modified DB? I use S7-1200 from TIA 10.5, now TIA 12 still not solve this problem. This made me want to leave S7-1200...really too upset
HOWERLIN Posts: 25 Rating: (0)
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This contribution was helpful to 1 thankful Users AutoGen_8323444

2/26/2014 2:25 PM	Rate (0)
m_turk Posts: 25 Rating: (0)	Just use snapshot -> snapshot2start values whan you really need to modify the DB, but when you come to a working machine, just create a new DB, dont modify the old one...
m_turk Posts: 25 Rating: (0)
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12/5/2016 12:04 PM	Rate (0)
Min_Moderator Platinum Member Joined: 9/3/2014 Last visit: 3/13/2019 Posts: 4766 Rating: (122)	New question published by KCD is split to a separate thread with the subject Retain variable after update/download datablock. Best regards Min_Moderator

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