11/2/2010 8:02 PM | |
Posts: 24 Rating: (0) |
hello see the attachment.analog input redundancy in other PLCs.the current converted to current then by using a resistance converted to voltage (same idea in simatic) and share by two channels.simple? is it used in simatic family.feasible or not. AttachmentREDUNDANCY.zip (300 Downloads) |
Last edited by: ELSAVAN at: 11/2/2010 8:13 PM |
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11/3/2010 12:24 PM | |
Joined: 1/28/2009 Last visit: 10/11/2024 Posts: 6852 Rating: (1365) |
Hello check this manual from phoenix contact.IT does what you need.One original signal is duplicated and they are totally isolated.(reference) You can implement the graphic that you draw by your own and test if it is reliable or not! In which PLC did you check this module/ Best reagards |
Last edited by: hdhosseini at: 11/3/2010 12:28 PMLast edited by: hdhosseini at: 11/3/2010 12:27 PM |
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This contribution was helpful to1 thankful Users |
11/3/2010 10:53 PM | |
Joined: 7/2/2008 Last visit: 9/30/2024 Posts: 928 Rating: (308)
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Hello ELSAVAN,
I hope I understood your question correctly. The answer is yes. It is possible and feasible. Your scheme is called Indirect current measurement. You can find the same scheme in the attached PDF which is extracted from S7-400H manual. It just gives you an escape from diodes. It's always easier to put a resistorrather than using2 diodes. I'm always a fan of current measurement but not with diodes (2 isolated 4-20mA) Ifyou are looking for isolation asappreciated by hdhosseini then you should put a repeater/splitter. You can find the same above splitter in P+F (Pepperl-Fuchs) & MTL as well. Best regards. H-H |
11/3/2010 11:42 PM | |
Joined: 10/7/2005 Last visit: 10/13/2024 Posts: 3024 Rating: (1054)
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Hello ELSAVAN just in case you are designing a "real" S7-400 H (or F/FH) system with afair amount of redundant AI's(and/or DI's, DQ's, AQ's) you may be interested in the Marshalled Termination Assemblies (MTAs)(manual can be found HERE). |
Cheers |
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This contribution was helpful to1 thankful Users |
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