10/26/2011 5:14 PM | |
Joined: 7/2/2008 Last visit: 8/26/2024 Posts: 928 Rating:
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HelloIICS, I recommend to study theS7-400H manual(chapter 10.5) anConfiguration of Redundant I/O Modules. Although the second document is used for PCS7, but you can still use it to know how to configure the redundant I/Os in hardware configuration and to know how it works. Each module has a unique address. So, you can't say I0.0 of module 1 and I0.0 of module 3. You don't need any OR gate to choose which module is active.
You need the following blocks: ● FC 450 "RED_INIT": Initialization function ● FC 451 "RED_DEPA": Initiate depassivation ● FB 450 "RED_IN": Function block for reading redundant inputs ● FB 451 "RED_OUT": Function block for controlling redundant outputs ● FB 452 "RED_DIAG": Function block for diagnostics of redundant I/O When you use these blocks correctly in your user program, the CPU will be able to detect which module is healthy and which is not and will do the comparison for you according to the criteria you select in HW configuration. Redundant analog output modules output a minimum current of approximately 120 µA per module, in other words a total of approximately 240 µA if they are passivated or if the CPU changes to STOP. Taking into account the tolerance, this means that a positive value is always output. A configured substitute value of 0 mA will result in at least these output values. In redundant mode, the configuration of the current outputs in case of a CPU STOP is set automatically to "no current or voltage". For digital outputs, all you have to do is to select the redundant modules in HW configuration. Both outputs will always have the same output value and when one of them fails the other is still giving the correct value. Best regards. H-H |
Last edited by: H-H at: 10/26/2011 7:02 PMAdded digital outputs paragraph |
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10/27/2011 10:56 AM | |
Joined: 7/2/2008 Last visit: 8/26/2024 Posts: 928 Rating:
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HelloIICS, Always use the lower address. So you will use I0.0. You still have to go for the lower address which is "IW256" notP IW256 .In redundant I/Os you always have to work inside process image area which means you are not allowed to access PIW256 because In this case you will be accessing the module itself regardless the correct value that might come from PIW512. In other words, the RED_IO blocks compare PIW256 with PIW512 and the correct value is stored inIW256. Best regards. H-H |
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10/27/2011 11:29 AM | |
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Thanks dear H-H your really helpful and indeed you are. |
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6/17/2016 11:23 AM | |
Joined: 8/21/2014 Last visit: 8/30/2024 Posts: 1006 Rating:
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New question published by freedom2 is split to a separate thread with the subject Redundant CPU 414-5H module. Best regards |
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