6/9/2008 7:51 AM | |
Joined: 9/28/2005 Last visit: 8/27/2024 Posts: 2957 Rating:
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Hello, Recently I had H system with redundant WinCC. In H system you must also use 2 PLCs, but both must be on the same (H) rack and both PLCs must be with "H". The thing is that one PLC is master and excecuting program while the other is standby and just waits. If master PLC fails, the standby PLC switches to master mode and continue to work. So your system will never go down (basically). You also have redundant connections with H system, so all your signals are also redundant i.e. if one profibus wire is cut, the other will be functioning. If you'll have just 2 PLCs it won't be high availability, because there will be different programs running on these PLCs. So I think if you want to use H system, you must consider: 1. Buying two H PLCs 2. Buying special H rack 3. Buying special ET modules with active backplane (if you'll need ET modules) 4. Buying S7-Redconnect program to communicate with WinCC And the best thing is to read some manuals and FAQs. http://support.automation.siemens.com/WW/view/en/1186523 http://support.automation.siemens.com/WW/view/en/2201072 http://support.automation.siemens.com/WW/view/en/22916606 http://support.automation.siemens.com/WW/view/en/22918919 Regards, |
Best regards, |
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6/9/2008 4:29 PM | |
Joined: 9/28/2005 Last visit: 8/27/2024 Posts: 2957 Rating:
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You'll need redundant WinCC option for this. You'll need to buy: 1. WinCC server license 2. S7-Redconnect license (as allready mentioned) 3. WinCC redundant license You'll need two computers for this with two monitors. If one fails, second computer takes control (like H PLCs). Every monitor must be connected to each computer. http://support.automation.siemens.com/WW/view/en/1144400 http://support.automation.siemens.com/WW/view/en/22059357 http://support.automation.siemens.com/WW/view/en/26331252 http://support.automation.siemens.com/WW/view/en/22811798 http://support.automation.siemens.com/WW/view/en/24075101
If you want to capture signals <=1ms, then at least your program cycle must be less than 1ms, but the best way is to use high speed counters. For more information you must see manual for CPU and modules. There you can find any data you need: http://support.automation.siemens.com/WW/view/en/1117645 http://support.automation.siemens.com/WW/view/en/1117740 http://support.automation.siemens.com/WW/view/en/14016796 http://support.automation.siemens.com/WW/view/en/23904550 Regards, |
Best regards, |
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6/9/2008 5:06 PM | |
Joined: 10/31/2005 Last visit: 9/4/2024 Posts: 366 Rating:
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Darius, thank you very much for this very informative response... |
6/9/2008 11:11 PM | |
Posts: 487 Rating:
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I think there is a cheaper option by using a module like 6ES7 321-7BH01-0AB0 This is a digital input module with process interrupt. The process interrupt of this module has following possibilities SM 321; DI16xDC24V can trigger a process interrupt for each channel group at the positive, negative, or both edges of a signal transition. Program each channel group separately. The parameters can be changed at any time (in RUN mode in the user program.) Active process interrupts trigger process interrupt processing in the CPU (OB40) and interrupt execution of the user program or of object classes with lower priority in the CPU. You can define the response of the AS to signal edge transitions in the user program of process interrupt OB40. The module acknowledges the process interrupt when the program exits the process interrupt OB. The module can save one interrupt per channel to the stack. If no higher priority classes are pending processing, the CPU processes the buffered interrupts (of all modules) in the order of their occurrence. |
6/27/2008 4:57 PM | |
Posts: 12 Rating:
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At point of multiple failures SCADA should reach PLC to get the information. Otherwise consider redundant in all aspects. |
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