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Trigger an alarm with one state

Created by: AliMohammad MansooryKolahmal at: 4/29/2008 3:54 PM (6 Replies)

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4/29/2008 3:54 PM	Rate (0)
AliMohammad Manso... Regular Member Joined: 6/20/2007 Last visit: 9/30/2024 Posts: 18 Rating: (0)	Hi there. Normally in all my projects I used to trigger alarms in HMI when a bit is"0" but now which I try wincc flexible I undrestand that alarms are triggered when they are "1" !! For being in safe condition for example a line break it is necessary to trigger alarms with "0" state; I do not know is there any possibilty to change this way of working in wincc flexiblevice versa or not? If there is no chance to change it I shall then change all my PLC program structure!!!!! Thanks for any recommendation in advance.

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4/29/2008 4:30 PM	Rate (0)
The Brain Gold Member Joined: 10/19/2005 Last visit: 11/30/2020 Posts: 1611 Rating: (121)	Hi, that are true -> alarms are triggered when they are "1" Info about "alarm messages" you will find for sample under this link -> http://support.automation.siemens.com/WW/view/en/19439876 or lookto this manual -> http://support.automation.siemens.com/WW/view/en/18660846 regards,

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4/29/2008 11:42 PM	Rate (0)
Scott Bronze Member Joined: 10/23/2005 Last visit: 3/31/2020 Posts: 81 Rating: (9)	Brian, Remember that alarms have to be in bit of Words, also. In your PLC program it is easy to do an exclusive OR to another set of words to get the correct state.

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4/30/2008 8:52 AM	Rate (0)
AliMohammad Manso... Regular Member Joined: 6/20/2007 Last visit: 9/30/2024 Posts: 18 Rating: (0)	Hi Brain, That is exacly the problem I have, I want to trigger the alarm with "0" because my program struture is like that. Now the question is: Is there any possibilty to configure wincc flexible to trigger alarms with "0"? If notI shall rewrite all my program structure.

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4/30/2008 12:15 PM	Rate (0)
ZAK Gold Member Joined: 5/8/2006 Last visit: 4/29/2024 Posts: 1085 Rating: (77)	Hi, you can createtwo tags - one internal tag and one tag with plc connection. If you use the system function "InvertBitInTag" on the event "change value" of the tag with the plc connection you can change a bit of the internal tag. The internal tag is the trigger bit of discrete alarms. The start value of the bitshould be "1"in your plc. Another wayto showalarm messagesare theanalog alarms in WinCC flexible. You can use the trigger mode "on falling edge" and the limit "1". Bye

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4/30/2008 5:10 PM	Rate (2)
Jeebs Posts: 218 Rating: (28)	Hi, No need to change your PLC structure. Assuming you are using S7 PLC then you can do the following: L MD20 // This contains the errors. This is part of your current alarm tag. L 2#110111100001110111100111 // The 1's represent the bits you want to invert, or rather which are 0 on alarm. XOD // Exclusive OR double word T MD120 // This is your new alarm tag for which a 1 represent alarm present and 0 for no alarm. If each and every alarm needs to be inverted, then it's quite fast. If not, then it's gonna take some time to get all the bits..:D If not using a S7 PLC then I'm sure other brands can do the same.
Jeebs Posts: 218 Rating: (28)
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5/1/2008 12:12 PM	Rate (0)
AliMohammad Manso... Regular Member Joined: 6/20/2007 Last visit: 9/30/2024 Posts: 18 Rating: (0)	thank you Jeebs it seems it is is the most effective and easy way I have all my alarm in one data block I read word by word separatly and XOR them with 1 and all of thiswill take aminute to do. thanks again!

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