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possibility of For-Next loop?

Created by: pici_c at: 4/23/2008 8:38 PM (7 Replies)

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4/23/2008 8:38 PM	Rate (0)
pici_c Posts: 80 Rating: (2)	Hi! How can I create a For-Next loop in LAD? I''ve tried the reverse jump case (first the label,then the JMP) but the PLC stopped.. And how can I index an array with a variable, like Array[variable] in LAD? (so I could address each array element in one PLC cycle) Thx: pici_c
pici_c Posts: 80 Rating: (2)
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4/23/2008 9:05 PM	Rate (1)
Late Platinum Expert Joined: 1/7/2006 Last visit: 11/17/2023 Posts: 2705 Rating: (318)	pici_c How can I create a For-Next loop in LAD? I''ve tried the reverse jump case (first the label,then the JMP) but the PLC stopped.. And how can I index an array with a variable, like Array[variable] in LAD? (so I could address each array element in one PLC cycle) Hi, I don't know how to program it in LAD, that would be not that easy, in STL it looks like this: L L#1 //Load the integer constant (32 bit) into ACCU 1. T MD20 //Transfer the contents from ACCU 1 into MD20 (initialization). L 5 //Load number of loop cycles into ACCU 1-L. NEXT:T MW10 //Jump label = loop start / transfer ACCU 1-L to loop counter. L MD20 * D //Multiply current contents of MD20 by the current contents of MB10. T MD20 //Transfer the multiplication result to MD20. LMW10 //Load contents of loop counter into ACCU 1. LOOPNEXT//Decrement the contents of ACCU 1 and jump to the NEXT jump label if ACCU 1-L > 0. L DBW [#test] where #test is a temp declared as dword I really don't know how to do this in LAD, but if you call a FC or FB from LAD and declare the program in STL then it will work fine. This type of commands is not really possible in LAD I think.
	I hope that the answer will help, if you have still questions, don't hesitate to ask me. All the best, Late Never say never, think in solutions, not in trouble......
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4/24/2008 12:40 AM	Rate (0)
Phantom75 Posts: 2661 Rating: (279)	pici_c: You can do this using the JMP, JMPN and LABEL instructions. Of course as Late has indicated, it is quite cumbersome to do this in LAD since practically there are no control structures existing in LAD. It is much easier to do this in STL or even better SCL. Regards
Phantom75 Posts: 2661 Rating: (279)
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4/24/2008 7:32 AM	Rate (0)
Aret Posts: 2348 Rating: (264)	Late is right as always - you can't use indirect addressing in LAD. You can try only this -declareANYvariableinTEMParea, fillit(accordingstructure (see in help),10h,data_type,repetition_factor,DB_number,pointer) withWAND_W,WOR_WcommandsonL-area.ThencallSFC20(BLKMOV)andgetresult. But this is really weird - plus you use absolute addressing of L-area and this method is definetely not good. So use STL:^)))
Aret Posts: 2348 Rating: (264)
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4/27/2008 5:41 AM	Rate (0)
Phantom75 Posts: 2661 Rating: (279)	pici_c: Is your problem of achieving a FOR-NEXT loop in LAD solved? Or do you need a sample program? Regards, Phantom
Phantom75 Posts: 2661 Rating: (279)
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4/27/2008 2:28 PM	Rate (0)
pici_c Posts: 80 Rating: (2)	Hi Phantom75! I couldn't solve my problem, so if it is possible, please send me a program example! thaks! pici_c
pici_c Posts: 80 Rating: (2)
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4/29/2008 8:34 AM	Rate (0)
wolpi@ts Silver Member Joined: 3/6/2006 Last visit: 9/13/2024 Posts: 369 Rating: (101)	Hello pici_c, see an example created by SCL-compiler. Regards Thomas Attachment For_Next.pdf (349 Downloads)

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4/30/2008 1:56 AM	Rate (0)
Phantom75 Posts: 2661 Rating: (279)	pici_c: Find attached the loop example in LAD. Import the AWL source in to your block and change view to LAD and save once. The main body of the program should be included in network(s) where I have the test counter. Let me know if this is helpful. Regards, Phantom Attachment LAD_LOOP.zip (331 Downloads)
Phantom75 Posts: 2661 Rating: (279)
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