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Triggering Global Alarm Window

Created by: NovoWorld at: 10/20/2009 8:41 PM (7 Replies)

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10/20/2009 8:41 PM	Rate (0)
NovoWorld Posts: 15 Rating: (0)	Struggling with triggering global alarm window. I believe that everthing in the alarm editor is correct - I have the Trigger Settings: Tag = to %MW120 and the bit = 3. So I have a PLC tag - Bool -MW120.3 that should trigger the global alarm window in any of my screens in runtime. Not happening. Does anyone have a example of tagging alarm windows and trigger them?
NovoWorld Posts: 15 Rating: (0)
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10/21/2009 3:37 AM	Rate (0)
NovoWorld Posts: 15 Rating: (0)	Guess I need to go back to class and get a reminder on bit and word addressing. %MW120- bit 3 is %M121.3 not %M120.3 Do not understand why the bit address goes right to left - but will not get hung up on this again. Changed all alarm bits to match my triggers and the alarm window works great. Sorry about the question.
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10/21/2009 9:37 AM	Rate (0)
Robster Gold Expert Joined: 5/28/2008 Last visit: 10/23/2024 Posts: 1343 Rating: (141)	Hi, to understand the problem, maybe this link helps: [url]http://support.automation.siemens.com/WW/view/en/29155499[/url] regards

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11/29/2009 8:58 PM	Rate (0)
andre* Posts: 16 Rating: (0)	Could someone explane this a little further? Pls, I had trouble mapping the alarm bits to words.
andre* Posts: 16 Rating: (0)
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11/30/2009 9:46 AM	Rate (0)
Robster Gold Expert Joined: 5/28/2008 Last visit: 10/23/2024 Posts: 1343 Rating: (141)	Hi, as you know one Word consist of two bytes or 16 bits. E.g. you have a word MW120. So it consist of the lowest value byte MB120 and highest value byte MB121. The problem is the storage organization in S7-1200. It stores the highest value byte in the lower data address in memory. So you get highest und lowest byte distored in S7-1200 memory. Thats why you have the first Bit at M121.0. The 8th bit is at M120.0. I agree its a little bit confusing, but if you know, what to do, you can handle it. regards

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12/2/2009 3:57 AM	Rate (0)
andre* Posts: 16 Rating: (0)	Robster, I think I understand. Could you take a look at the attached file and see if I understand it right. I appreciate the info. That explains a lot if I have it right. My main issue as of late has been assigning bits to alarms. I would get the value of the word and the bits didn't make sense. Different from what I learned in college. Attachment New Compressed (zipped) Folder.zip (473 Downloads)
andre* Posts: 16 Rating: (0)	Last edited by: andre* at: 12/2/2009 4:01 AM
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12/2/2009 10:30 AM	Rate (0)
Robster Gold Expert Joined: 5/28/2008 Last visit: 10/23/2024 Posts: 1343 Rating: (141)	Hi again, first table is okay. Second one not. If you have word value "1" in MW120, then Bit M121.0 is set. With value "32768" Bit M120.7 is set. You can easiely try it out by looking your MW in status chart. Watch MW120 in dezimal format. Watch also MB120 and MB121 in binary format. Now enter your values in MW and watch the bits in the both MB's. regards

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12/3/2009 2:57 AM	Rate (0)
andre* Posts: 16 Rating: (0)	Thanks again Robster, Iappreciate the time. So it is like this. See attached.
andre* Posts: 16 Rating: (0)
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