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[SOLVED] Scanning data in DB by using indirect addressing

Created by: Matilda at: 4/4/2011 11:20 AM (17 Replies)

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4/4/2011 11:20 AM	Rate (0)
Matilda Posts: 53 Rating: (1)	Hi! I'm trying to programme a function to scan trough a database with changing data. The data in db is in 'CHAR' datatype and theres 100 bytes of content. But I need to look for 2 CHAR at the same time so I'm using data type 'WORD' in the fuction. So far I've got this: OPNdb200 L DBW 0 LAR1 L 98 loop: T MW 20 L DBW [AR1,P#1.0] T #VAR_2 L MW 20 LOOP loop #var_2 is for using the content ofdbw in comparison (later in the programme), so I only need to be able to get the content of certain word from db to #var_2. I hope you get the point I'm trying to explain. I'm only getting the CPU to stop with my loop programme.... How can I get the function to go through the whole 100 bytes of data and returning the value of every word to #var_2? And though I put 98 to the loop counter, the programme should scan through the db all the time, since the data changes all the time... Thank you all in advance for you patience with my questions! -M
Matilda Posts: 53 Rating: (1)	Last edited by: Matilda at: 4/18/2011 7:39 AM Last edited by: Matilda at: 4/4/2011 11:56 AM Added some more info -M-
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4/4/2011 1:47 PM	Rate (0)
Aret Posts: 2348 Rating: (264)	0) L DBW0 LAR1 ///////////// Maybe you mean L P#DBW0.0? 1) AR1 doesn't change inside loop - you're constantly loading dbw0 2) Comparasion must be inside loop
Aret Posts: 2348 Rating: (264)
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4/5/2011 7:19 AM	Rate (0)
Matilda Posts: 53 Rating: (1)	Aret 0) L DBW0 LAR1 ///////////// Maybe you mean L P#DBW0.0? Yes, my intention was to use this one, but I keep getting "syntax error at DBW"... Aret 1) AR1 doesn't change inside loop - you're constantly loading dbw0 One of the problems I was trying to solve, but I couldn't figure out, how can I change the AR1 so the programme keeps running through the whole db? Aret 2) Comparasion must be inside loop Thanks!
Matilda Posts: 53 Rating: (1)
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4/9/2011 12:14 PM	Rate (0)
Aret Posts: 2348 Rating: (264)	0) Try L P#DBX0.0. If doesn't help - L DW#16#84000000 1) +AR1 P#2.0
Aret Posts: 2348 Rating: (264)
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This contribution was helpful to 1 thankful Users Matilda

4/14/2011 9:34 AM	Rate (0)
Matilda Posts: 53 Rating: (1)	Thanks for the help, but I tried these, and still getting the CPU to stop... Should the +AR1 and rest of the indirect addressing commands work with 315 2DP CPU? From CPU diagnostics I get message "There is a programming error but the corresponding OB (OB121) or FRB is either not loaded or has not been activated."
Matilda Posts: 53 Rating: (1)
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4/14/2011 11:10 AM	Rate (0)
MM1234 Posts: 270 Rating: (53)	Matilda From CPU diagnostics I get message "There is a programming error but the corresponding OB (OB121) or FRB is either not loaded or has not been activated." Hi Matilda, I'm not entirely sure, but shouldn't there be another message in the CPU, rightbefore this one, that says the actual error?
MM1234 Posts: 270 Rating: (53)
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4/14/2011 11:18 AM	Rate (0)
Aret Posts: 2348 Rating: (264)	1) Indirect addressing works on 315 for sure 2) Download OB121 (may be empty), check if Db200 is downloaded 3) Debug your program step-by-step - then you can find out what is wrong:^) PS. I can just publish solution if you want, but it would be better if you'll make it by yourself
Aret Posts: 2348 Rating: (264)	Last edited by: Aret at: 4/14/2011 11:19 AM
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4/14/2011 10:07 PM	Rate (0)
RandomCoder Experienced Member Joined: 8/16/2010 Last visit: 7/8/2024 Posts: 50 Rating: (8)	I normally find that the PLC errors becauseI have attempted to address a datablock address that doesn't exist. Have you tried using a smaller range and if this is ok just expand on it to get a better idea of what is happening. It is often better to start small and grow the function to do what you want. Regards, RandomCoder

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4/18/2011 6:42 AM	Rate (0)
Matilda Posts: 53 Rating: (1)	Thanks again for the help! Aret PS. I can just publish solution if you want, but it would be better if you'll make it by yourself And yes, please DON'T publish it. Not yet at least, I gotta torture myself with the problem for a while longer... Learning process going on.
Matilda Posts: 53 Rating: (1)	Last edited by: Matilda at: 4/18/2011 7:37 AM So in this case, I just hadn''''''''''''''''t downloaded the OB121, and downloading that one seemed to solve the problem. :) Thanks for the help guys! Last edited by: Matilda at: 4/18/2011 6:42 AM
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4/26/2011 9:18 AM	Rate (0)
Matilda Posts: 53 Rating: (1)	Cheered too early... I made the programme in my test environment and when I moved it to the working plc, I only end up getting AR1 result to the var_2... So yes, AR1 is changing, but for some unknown reason var_2 gets numbers from 0-100 instead of the contents of the DBW0-DBW100 as it did on my test environment.
Matilda Posts: 53 Rating: (1)
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