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Finding absolute address

Created by: Krumins at: 7/7/2011 1:00 PM (8 Replies)

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7/7/2011 1:00 PM	Rate (0)
Krumins Regular Member Joined: 10/11/2010 Last visit: 2/4/2025 Posts: 12 Rating: (0)	Hello all! Is it possible to retrieve the absolute address from a STAT? I`m not interest in the content of for example my_array[0], bur rather the address this got. I can not use a static address as the instance DB changes. Regards, Christian

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7/7/2011 2:09 PM	Rate (0)
hdhosseini Diamond Expert Joined: 1/28/2009 Last visit: 1/2/2026 Posts: 6891 Rating: (1368)	Krumins Hello all! Is it possible to retrieve the absolute address from a STAT? I`m not interest in the content of for example my_array[0], bur rather the address this got. I can not use a static address as the instance DB changes. Regards, Christian If you are using STAT in a FB and want to access it in your programming simply use the symbolic name you used while defining the variable.Also possible using indirect addressing.Consider , we want to manipulate an element in an array (e.g name of array is hd ) which is defined in STAT, So check the possibilities: [code] L hd[5] // load a word L 5 +I T hd[6][/code] Out side the FB,each time you call the FB,a DB assigned and you should find the corresponding DB cell for each application you call the it! Also,clarify you question to provide a clear answer to you. Regards
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7/7/2011 3:16 PM	Rate (0)
yy1 Posts: 535 Rating: (112)	Dear Krumins, you can get the adress of a stat with this code: [code] LAR1 P##stat1 L W#16#affe T DIW [AR1,P#0.0] [/code] It is also possible to use [code] L P##stat1 //Load the pointer to the specified parameter in ACCU 1. // (This instruction loads the relative address offset of the specified parameter. // To calculate the absolute offset in the instance data block in multiple instance FBs, // the contents of the AR2 register must be added to this value. [/code] Best regards, yy1
yy1 Posts: 535 Rating: (112)
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7/7/2011 3:45 PM	Rate (0)
Krumins Regular Member Joined: 10/11/2010 Last visit: 2/4/2025 Posts: 12 Rating: (0)	I`m using the absolute address in a loop to check a DB for changes. TheDB is loaded in to the array at startup. As I need to increment the address Ineed the absolute value to the array located inan Instance DB. Ifchange is detected, I want toupdate the array, and update a third DB aswell. I`m not too familiar with adress registers, so I`m trying to find the best solution for this, here`s what I`ve come up with so far..: OPN DB [#DATA_DB] L 20 //Offset SLD LAR1 L P##DATA_ARRAY LAR2 L 100 back: T #LOOP_COUNT L DIB [AR2,P#0.0] T #COMP_VALUE_ARRAY L DBB [AR1,P#0.0] T #COMP_VALUE_DB L #COMP_VALUE_ARRAY <>I = #NOT_EQUAL A #NOT_EQUAL JCN equa OPN DB [#OBJ_DB] L #COMP_VALUE_DB T DIB [AR2,P#0.0] T DBB [AR1,P#0.0] OPN DB [#DATA_DB] equa: L P#1.0 +AR2 +AR1 L #LOOP_COUNT LOOP back

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7/7/2011 3:55 PM	Rate (0)
hdhosseini Diamond Expert Joined: 1/28/2009 Last visit: 1/2/2026 Posts: 6891 Rating: (1368)	Hi It is better to use indirect addressing for complex data structure such as DATE and TIME(8-BYTE).It is possible to use indirect addressing, but it is really complex.Using the symbolic name is much easier! Regards
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7/7/2011 4:13 PM	Rate (0)
yy1 Posts: 535 Rating: (112)	You have the possibilities to use symbolic adressing (as hdhosseini suggested) copy the content of your arrays using the SFC20 'BLKMOVE' do it, as you started - but this is certainly the hardest way Best regards, yy1
yy1 Posts: 535 Rating: (112)
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7/7/2011 4:18 PM	Rate (0)
hdhosseini Diamond Expert Joined: 1/28/2009 Last visit: 1/2/2026 Posts: 6891 Rating: (1368)	Dear Krumins It is better provide more information such your s7 program, then we are able to offer better (or optimum) solution. regards
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7/7/2011 5:13 PM	Rate (0)
Krumins Regular Member Joined: 10/11/2010 Last visit: 2/4/2025 Posts: 12 Rating: (0)	Thank you for your replies. I cant see how I can use symbolic addressing without making an extremely long comparison logic. The DB`s I`m comparing consists of just over 3000 bytes, so the loop will be just as long. I could of course compare Dint`s, but it would still almost be almost 1000 compares. Only reason I started with this was because I thought I could use a variable in an array, like test_array[loop_count], apparently I could not and now I cant rest until I find the proper way to do it in STL. I`d hate to do leave it without a solution and start over in SCL.. Unfortunately I cant provide the s7 program as this is a running software under company license

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7/7/2011 8:10 PM	Rate (0)
hdhosseini Diamond Expert Joined: 1/28/2009 Last visit: 1/2/2026 Posts: 6891 Rating: (1368)	Hi You want to use an external DB in a function so if possible use UDT to have pattern in your DB for easier process of data.When adding an extra data in a UDT, changes updated and by indirect addressing the programming effort is minimized. Regards
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