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REGARDING VALUES STORING IN DBs

Created by: samkcr at: 5/17/2009 6:59 PM (6 Replies)

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5/17/2009 6:59 PM	Rate (0)
samkcr Bronze Member Joined: 3/24/2009 Last visit: 3/20/2023 Posts: 406 Rating: (3)	Hi.... How to clear the values in DB ? Bcoz while using DB values for our process even though there is no updation in field the past value is stored inDB. i have to clear those values when the process was stop without using any move fn or something.... Is it possible?
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5/18/2009 9:04 AM	Rate (0)
Sydney Gold Member Joined: 1/4/2008 Last visit: 3/8/2023 Posts: 703 Rating: (96)	Hello, you can use SFC21 "FILL" or after process finishes delete the DB with the SFC23 "DEL_DB" and at start create a new DB with the SFC22 "CREAT_DB". You can also read the DB with start values from the load memory with the SFC 83 "READ_DBL". Regards Sydney

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This contribution was helpful to 1 thankful Users Saruca

5/26/2009 7:43 PM	Rate (0)
samkcr Bronze Member Joined: 3/24/2009 Last visit: 3/20/2023 Posts: 406 Rating: (3)	Hi... Thankyou for your reply... If we will usethis SFC23 the total DB is deleted in the program ? OR Only values.... How it will act i didn't know how to use? Will u explain me ? I already studied the help of SFC23 But i can't get it............. Sorry for the late reply....
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5/27/2009 11:32 AM	Rate (0)
Sydney Gold Member Joined: 1/4/2008 Last visit: 3/8/2023 Posts: 703 Rating: (96)	Hello, I forget that after creation ofa DB with the SFC CREAT_DB it contains random data so it have to be alsoinitialized.I suggest to use the SFC FILL with zero to delete all the data from your DB. Declaration in TEMP area: dwClear of type DWORD iRetVal of type INT The code: L 0 T #dwClear A<#bProcessStartImpulse> JCN End CALL "FILL" BVAL :=#dwClear RET_VAL:=#iRetVal BLK :=<"DBdata".data> End: NOP 0 Regards Sydney

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5/27/2009 7:02 PM	Rate (0)
samkcr Bronze Member Joined: 3/24/2009 Last visit: 3/20/2023 Posts: 406 Rating: (3)	Hi.... Thanks a lot.... For my case i have to clear the DB2.DBD0 ....DB2.DBD16.The following modified program is correct? L 0 T DB1.DBD 0 A "M0.0" JCN End CALL "FILL" BVAL :=DB1.DBD0 RET_VAL:=MW1 BLK :=DB2.DBD0 End: NOP 0 For process start impulse input what is the correct value i have to give? Bcoz this DB i am using for storing the meter value by usingCP341 communication..... In case of communication failure the last value is stored in this DB...
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5/28/2009 10:53 AM	Rate (0)
Sydney Gold Member Joined: 1/4/2008 Last visit: 3/8/2023 Posts: 703 Rating: (96)	oops, I thought you need to delete a big amount of data Just to correct the code,BLK has to be defined as the whole area so it should be the complete ANY pointer, the symbolic representation would be better.But you need just five doublewords so it's vain to call the SFC, the code could look like: A"M0.0" JCNEnd L 0 TDB2.DBD0 T(DB2.)DBD4 T(DB2.)DBD8 T(DB2.)DBD12 T(DB2.)DBD16 End: NOP 0 If you don't use the symbolics then the "DB2." in the brackets isn't necessary, it's faster butthe doublewordswon't be in the cross references as used. I'm afraid if I could help you rightwith the impulse which enables this clearing, you have to decide yourselfaccording to process on which time it would be done. If you want to clear it when the comm fails you could use the information from the communication blocks or if you have some "watchdog" included in the data... Another thing is what data types are these five doublewords? If it contains for example REAL format this code makes it invalid (it won't be 0.0) and ifit's accessed before saving a new data, itwould make the problems somewhere. Regards Sydney
	Last edited by: Sydney at: 5/28/2009 10:55 AM
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5/28/2009 5:29 PM	Rate (0)
samkcr Bronze Member Joined: 3/24/2009 Last visit: 3/20/2023 Posts: 406 Rating: (3)	Hi.... These double words are DINT type........ Ok i will check it and then come back.... thanks.......
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