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| 3/26/2020 8:51 PM | |
Joined: 3/24/2018 Last visit: 12/29/2024 Posts: 236 Rating:
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Hi, what do you mean by delay alarm? |
| 3/26/2020 8:52 PM | |
Joined: 9/27/2006 Last visit: 4/19/2025 Posts: 12346 Rating:
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Hello Pepsi Cola; What is the relationship of the 2 CPUs, as far as Profibus is concerned? Is the PLC in cabinet #2 a slave to the CPU in cabinet #1? Why you should check that: when a Profibus-DP master gets power and becomes active, it starts polling the slaves that have been setup in its Profibus configuration. If a slave des not answer, it will try again in the next Profibus cycle, and attempt again, until the slave is declared faulty. Then it will not attempt to contact it again, it will take the slave out of the polling cycle; you must reset the master so that it restarts its polling cycle and eventually sees the response from the slave that is now active. If this is the case, one option is to use SFC 12, D_ACT_DP, that is designed to remove a slave temporarily from the master's polling cycle, when you take it out physically for maintenance, for example. See these FAQs: What should you pay attention to when operating a DP slave temporarily on a PROFIBUS DP network? (Note: this FAQ proposes a sample program showing how to use SFC 12.) https://support.industry.siemens.com/cs/ww/en/view/15014658 Enabling a disabled DP slave with SFC 12 'D_ACT_DP' https://support.industry.siemens.com/cs/ww/en/view/19730984 I suggest that in your program you setup SFC 12 for theat slave CPU 318-2DP, and make it active before you shutdown power. When you have powered up cabinet #1 and cabinet #2, use SFC 12 again to re-activate the slave CPU in the master's program. The master will see the active slave and continue polling without problem. If I am making a complete mistake here, please give us more details so we can evaluate a solution that fits your issues. Hope this helps, Daniel Chartier |
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