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Can anyone tell whatfor BLOCK_FC, BLOCK_FB etc. types are used?
Created by: Aret at: 7/8/2010 9:08 AM (1 Replies)
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| 7/8/2010 9:08 AM | |
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Can anyone tell whatfor BLOCK_FC, BLOCK_FB etc. types are used? I couldn't find the answer:^) Splitted from How is an ANY pointer structured?. |
Last edited by: O_Moderator at: 7/8/2010 11:26 AMnew subject after splitting |
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| 7/8/2010 11:02 AM | |
Joined: 10/7/2005 Last visit: 11/12/2024 Posts: 3027 Rating:
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As for Aret's question, I think I can at least offer a possibleexplanation for the reason behind the existence of the BLOCK_FC,BLOCK_FB & BLOCK_DBParameters which is: Ensuring backward compatibility for the conversion ofS5 programs to S7. S5 had the "B" (Block) Parameter for FB's which couldbe used to pass on a DB,PB, FB,etc. Step 7 still offersthis "feature"(or functionality) but replacesthe generic "B" Parameter with dedicated BLOCK_FC, BLOCK_FB & BLOCK_DB ones. BLOCK_DB (or "B" Parameter with a DB xyz value attached to it) was actually commonly used in S5 days as S5 did NOT offer the "complete Addressing" method but only the "partial addressing" method. For exampleusing "DB1.DBW8" as an addres orParameter was NOT possible, you had to explicitly openDB1 followed by access to the DW8 in this example, hence there was a realneed to be able to pass DB's on as parameter to FB's. BLOCK_FC & BLOCK_FB (or their S5 counterpart) werehowever rarely used even in S5 days (as far as I'm concerned anyhow) and I never had to use these in S7 either thus far. Having said all this, I still really like to know the usefulness of the the BLOCK_SDB Parameter and am still hoepful toget feedback(or answers) for THIS thread (thanks for posting the question here Aretas it reminded me of my dormant thread). |
Last edited by: O_Moderator at: 7/8/2010 11:25 AMCheers |
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