7/9/2010 2:37 AM | |
Joined: 10/7/2005 Last visit: 9/24/2024 Posts: 3022 Rating: (1054) |
Hello UMENCHO good question and here's my take on SFC46: One reason to use it to be able to have a converted S7 program behave like the original S5 program (which had a simple"STP" command to cause a user program initiated CPU Stop). Another one is to simply be able to selectively put thethe CPU into a safe state (which CPU Stop typically is). Take the following example: You do NOT want to cause a general CPU if a diagnostic interrupt occurrs which means you must add OB82 toyour PLC to begin with. You do however want to cause a CPU stop on certain Diagnostic events. You can now add some discrimination logic to OB82 and selectively decide which Diagnostic Events will lead to a call of SFC46 and which ones don't (Report System Error does the same based on what tick mark is set in the "CPU in Stop" tab). And a rather unorthodox usecase would be this: You may be involved with the commissioning of a Plant in a rather nice and exotic corner of this Planet and have such a good time that would like to be called back one day in the future. You now simply add SFC46 togetehr withsome time or event based based logic to a block,Know How Protect it and wait for the phone call tofly back to site to get the Plant up and running again. Don't think this "idea" is too far fetched, I know of one person (who I have little respect for and am not associated with) who did exactly this a long time ago in an S5 (his Plan did not go quite as plannedthough as his company did find out what he did in the logic, so take this last usecase as a warning instead of a useful suggestion). |
Cheers |
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This contribution was helpful to5 thankful Users |
7/11/2010 7:00 PM | |
Joined: 7/2/2008 Last visit: 8/26/2024 Posts: 928 Rating: (308) |
Hello UMENCHO, Just one more use of STOP command that Siemens offers. Check attachment. Best regards. H-H |
This contribution was helpful to3 thankful Users |
12/22/2011 10:34 AM | |
Joined: 7/15/2011 Last visit: 8/8/2024 Posts: 48 Rating: (0) |
Dear All, if i use this SFC46, and how will i make the plc bake to run mode?
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