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Can anybody tell me when it''s more convenient to use MCR instead of standard methods?
Created by: Aret at: 6/9/2011 2:52 PM (2 Replies)
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| 6/9/2011 2:52 PM | |
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Posts: 2348 Rating:
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[schnippschnapp] Actually i must ask if someone has practical experience with MCR - i never used it and know only theoretically how it works. Can anybody tell me when it's more convenient to use MCR instead of standard methods? Splitted from Notes should be considered while using MCR. |
Last edited by: O_Moderator at: 6/9/2011 2:55 PMnew subject after splitting |
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| 6/9/2011 4:03 PM | |
Joined: 10/7/2005 Last visit: 10/13/2024 Posts: 3024 Rating:
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Hello Aret no practical experience with MCR from my side as I refuse to use it and find it to be the most superflous instruction in a PLC (apart from the fact that its usage is easily fraud with Danger if the "fine print" is not read). While I can appreciate that the MCR instruction is simple meant to be the software equivivalent to the traditional hardwired Master Control Relay and that other PLC's have it too in their instruction set, I still find it utterly nonesensical. S5's didn't have it and it beats me why Siemens decided to add it to the S7 instruction set (possibly simply becauseit existsin other PLC's too). My advise: Stay away from it, you know what you are doing anyhow and while I'd be happy to hear arguments or stories about possible applications where MCR usage may be perceived to be useful, I fear nothing will persuade my ratherstubborn mind concerning this matter. |
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