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Indirect opening of DI register

Created by: Giuliano69 at: 1/22/2012 11:45 PM (1 Replies)

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1/22/2012 11:45 PM	Rate (0)
Giuliano69 Posts: 21 Rating: (0)	In FC Function, IN parameter can be declared Block_DB, but can ONLY be used with DB register and NOT with DI register: VAR_INPUT Block_DB1 : BLOCK_DB; Addr1 : Word; EDN_VAR OPN Block_DB1 // allowed instruction OPN DI Block_DB1 // not allowed The canonical solution is to pass a DB number for DI as a WORD OPN DI [Addr1]; ///allowed Why it is not possible to open DI with a BLOCK_DB IN parameter? It shoulb be more clean to read the code, beeing possible to use in the call the symbolic name of the DB and not only its number. The solution I use is to open first DB, then read the db number, use a WORD Addr TEMP variable and open DI: OPN Block_DB1 L DBNO T Addr2 OPN DI [Addr2] Nothing FASTER or CLEANER ?
Giuliano69 Posts: 21 Rating: (0)
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1/23/2012 12:26 AM	Rate (1)
fritz Diamond Expert Joined: 10/7/2005 Last visit: 6/3/2023 Posts: 2966 Rating: (1025)	Hello Giuliano69 you are correct, it isn't possible to do open a DI "directly" when BLOCK_DB is used as a FC parameter. As a"faster or cleaner" method to your indirect way, you can usethe "CDB" command (swap DB1 and DB 2 registers) which would look as followed in your example case: OPN Block_DB1 // Block _DB1 parameter is opened as "DB via DB1 register CDB // Swap DB1 and DB2 register --> Block _DB1 parameter is now open via DB2 (DI) register I hope this helps
	Cheers fritz The advice and opinion given in this thread is that of the author and does not necessarily reflect the views of I S Systems Pty Limited. To find out how I S Systems can help you with your automation needs please visit www.issystems.com.au.
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