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why the blocks are not executed normally in CFC?

Created by: 1magin at: 10/16/2012 8:14 AM (5 Replies)

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10/16/2012 8:14 AM	Rate (0)
1magin Posts: 7 Rating: (0)	HI,everyone, Did someone meet the event that blocks created by yourself could not be executed normally in CFCsometimes ? i mean i'm sure that the function logic is right, but the outputsdo not conform tothe statement logic inthefunction block,and sometimes,they suddenly changed unexpected. however,the blocks from PCS7 Standard Library are executed normally. i guess that it has relations to the CPU load. PS: hardware structrue:414-4H, with 5 racks , and 12 modules inserted on every rack. the block with problems are created by SCL,LAD and FBD.
1magin Posts: 7 Rating: (0)	Last edited by: 1magin at: 10/18/2012 9:29 AM
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10/16/2012 10:59 AM	Rate (0)
dmertens Bronze Member Joined: 10/3/2007 Last visit: 6/25/2024 Posts: 188 Rating: (34)	You will have to send us the source code of your blocks.

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10/17/2012 10:37 AM	Rate (0)
1magin Posts: 7 Rating: (0)	thx 4 ur attention,but you know,they are really the simplest codes,they worked about monthes,it happend to be unusual these days.i dont know why.
1magin Posts: 7 Rating: (0)
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10/22/2012 6:59 AM	Rate (0)
1magin Posts: 7 Rating: (0)	hi,i found that when i downloaded modified hardware configuration, also the library blocks could not work,like FB5.these blocks are in runtimes group OB35 with 1000ms,and the blocks worked again after i modified the parameter 1000ms to 600ms. Can someone tell me why that happened ？ i wonder the runtime mode of the AS,and thank you all.
1magin Posts: 7 Rating: (0)
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10/22/2012 8:33 AM	Rate (0)
dmertens Bronze Member Joined: 10/3/2007 Last visit: 6/25/2024 Posts: 188 Rating: (34)	FB5 is a timer block of which the execution cycle is defined by the SAMPLE_T input. This input is automatically set by the compilation process, so if you change the time of the OB in which your program runs without recompiling and downloading theprogram i'm quite sure your FB5 will no longer work properly. By the way, the normal setting for OB35 is not 1000 but 100ms. If you want to execute your logic in a 1000ms cycle it would be much better to move the logic to OB32 in stead of changing the timing. As you may have noticed, each cycle OBhas a specific priority and they are set in a way that the highest (fastest) OB has the highest priority to mae sure that slower (larger) programs can be interrupted by faster (shorter) programms. If you change these times there is no longer any guarantee that alower OB will still be able to execute its cycle when it gets interrupted by a program that takesnearly all the available time or even more. Kind regards, David

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10/22/2012 1:07 PM	Rate (0)
1magin Posts: 7 Rating: (0)	thank you ,while i clearly understand what u pionted out all above.i made some projects but i never met this phonomena before.also,this project is a little different,since that there are some internal faults just as the runtime of OB34 tiggers Time error and called OB80,and i had to clear the faults.after trying many times,the original flauts disappered only when i put blocks in OB34 runtime group into runtime groups OB32,OB33 and OB34 averagely with all 50ms.and the blocks existed in OB32 and OB33 before have to be moved into OB35,considering the quantities of blocks and the working load of 414,i changed the cycle from the default 100ms to 1000ms,which i thought i was right. this is reason why i changed the defaults. additionally,only a little FB5 didnt work,and im sure i had made compilings and downloadings after i changed the parameters. can you give me a better explanations？
1magin Posts: 7 Rating: (0)
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