DB Backup in S7

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Anonymous

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Hi! I'm looking for the way to make backup for S7-300. I'm find that the structure of DB offline with symbols don't match DB online in PLC. If I simply copy all DB online to offline project I loose all symbols. How is possible to make backup for DB and do not loose symbols?

Regards
Ed
 
DB

Hello Edgar,

you must copy the online-DB to a offline-projekt where the DB is present and overwrite it.

best regards
André Räppel
 
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to save online db, i create an other s7-progamm in the same project.
in this i copy all online db's.
so i can work with the normal offline-db with the symbols. but when i must restore the db online i can take the other one.
 
hello!

you have to create a programm which copies the data online for example from db1 to db2. db1 is the online db which includes the data, db2 is the offline db, which includes the symbols.
then you copy the db2 in the offline project and overwrite the offline db1.

regards
bernhard
 
why should he do this?
i save my online-db to save the aktual--parameter. if i overide this with an other db all my akt.para will overite.
 
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he wants to have offline the db with all symbols and data. if i'm wrong, please tell me!

for saving only the data, volkers version is ok. the plus of my version is, that you can watch the db.

bernhard
 
he have the offline-db with the symbols.
then he want to save his online-db.
if he overite the offline-db with the online-db, all symbols will be lost.

the way you tell will not function.
you have your offline-db with the symbols. then you copy the online-db to offline-db2. the db2 will not have any symbols. then you copy the db2 to db and overite the complete db with db2. the new db will not have any symbols.
 
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you are sure?

i can't test it in this moment.

but why will i lost all my symbols when i copy the online-db to the offline-db directly?
 
yes, because we use this procedure.

i don't really know, why you loose the symbol. i think that the problem comes from the absolut adressing of the simatic software. i think they use the symbol adresses like urls in the internet. when you chance the ip adress, but not the url, you cant watch the website again. i don't know, if this is right?!

i am looking for an siemens article i read a few weeks before. when i have found this article, i will send you the link.

bernhard
 
no, because the symbol is saved offline and not in the db. siemens already don't use a realy symbol adressing.

Yes but the symbols are stored in the Symbol table, not in the DB.

but why will i lost all my symbols when i copy the online-db to the offline-db directly?

Presumably because you overwrite the offline copy with the online one, instead of merging the two.

Maybe they will be preserved, depending on whether Symbolic or Absolute priority is set, must try it out some time.
 
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If you open the project offline first, and then go online (from the STEP7 Manager), and then highlight the DB's that you want to save, and then select "PLC" .. "Uplad to PG", then the Actual Values will be uploaded and the Symbols and comments in the offline file will stay.

I can think that there may be a problem if there is a timestamp conflict or something like that.
 
Please find the solution what I reseive from SimonG in another forum:

"Ok, for the case where the DB's are the same length, proceed as follows: Assume the DB you want to correct is DB1. Assume DB3 is currently not used.
In the offline folder, create DB3 as a copy of DB1 (use cut/paste and then rename).
Download DB3 to the plc.
Write some program in the plc (say ob1) which copies the contents of DB1 to DB3.
(e.g. if the DB's are 212 bytes long, use the following:
CALL SFC 20
SRCBLK :=P#DB1.DBX0.0 BYTE 212
RET_VAL:=MW900
DSTBLK :=P#DB3.DBX0.0 BYTE 212
)
Download to the plc. Make sure Mw900=0 to show the copy was ok.
Remove the copy program from OB1 and download to the plc, (DB3 now contains a copy of what is in DB1 in the plc).
Download DB1 to the plc.
Write some program in ob1 to copy DB3 back to DB1
(e.g.
CALL SFC 20
SRCBLK :=P#DB3.DBX0.0 BYTE 212
RET_VAL:=MW900
DSTBLK :=P#DB1.DBX0.0 BYTE 212
)
Download to plc. Make sure MW900=0 to show copy was ok.
Remove the copy program from OB1 and download to the plc.
Delete DB3.
Db1 can now be copied from the online folder to the offline folder for your backup.
For the DB's that are not the same length, you could use a similar procedure to the above, but the copy length will be the shorter of the two DB's.

Hope this helps.
"

I can only say that sometimes, when the timestemp is the same is posible simply copy db from PLC to project and we keep symbols, coments etc. But if we have differences is impossible backup aktual data na keep symbols in DB

regards
Ed
 
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