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Problem with cyclic-interrupt block adding

Created by: dejanH at: 9/24/2008 11:14 AM (4 Replies)

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9/24/2008 11:14 AM	Rate (0)
dejanH Posts: 32 Rating: (0)	Hi,I have problem to add new cyclic-interrupt OB. Since we have several priority classes (that should be processed in different time-slices) I would like to use several OBs of cyclic interrupt type. So I already use OB35 without of problems. Now when I tried to add OB38 I cannot edit it – it's desabled, in appendix I inserted my Cyclic interrupt tab of processor properties (processor is CPU 315 F-2 PN/PD) and when I try to download it I get error message “(D20C) OB cannot be copied as the associatedpriority class does not exist.” How can I configure the processor to use other OBs than OB35? Attachment Cyclic Interrupts.JPG (206 Downloads)
dejanH Posts: 32 Rating: (0)
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9/24/2008 11:38 AM	Rate (0)
AMAZINGAHMED Gold Member Joined: 8/27/2006 Last visit: 9/2/2024 Posts: 719 Rating: (88)	Since you found it dimmed in the HW configuration, then that CPU does not support that OB. If you want to do the excercise, try another CPU in your HW configuration e.g. 417H and you can see the difference.
	The more you know, The more you know that you don't know
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9/24/2008 1:33 PM	Rate (2)
FrankW. Posts: 162 Rating: (23)	Hi dejanH, the CPU-315 has only the OB 35. Which OB´s available, you can see in the state assemblies (Ctrl+D) performance data. Best regards FrankW
FrankW. Posts: 162 Rating: (23)
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9/24/2008 3:08 PM	Rate (2)
FunStuff Posts: 103 Rating: (10)	I have worked around this problem with a 315-2DP by setting my OB35 to some fast frequency that is a common denominator to all the cyclic frequencies I desire. I then use a counter that updates with OB35 to call each type of process needed. Example OB35 is set to 20ms. I want to call ProcessA at 20ms, ProcessB at 60ms. ProcessA will execute with each OB35 interupt, ProcessB will have Counter1 compared and incremented each time OB35 executes when it reaches 3 it will reset and call ProcessB.
FunStuff Posts: 103 Rating: (10)
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9/25/2008 9:07 AM	Rate (0)
AMAZINGAHMED Gold Member Joined: 8/27/2006 Last visit: 9/2/2024 Posts: 719 Rating: (88)	I saw this technique (using counter in OB) in a program where there are many PID loops that if all of them are executed in the same scan cycle, their execution time will exceed the scan cycle. Then the programmer uses this technique to execute some of them every scan cycle. By the way, these PID loops were used in a program which controls a slow process.
	The more you know, The more you know that you don't know
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