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11/18/2008 11:19 PM | |
Joined: 10/7/2005 Last visit: 4/26/2024 Posts: 3004 Rating: (1046) |
Hello Omega you are correct with your first assumption, that is if you loose power to theCPU closest ET200Sall PN Slaves downstream of it will be lost too. PN Slave failures other than loosing power to it (e.g. faulty I/O card, removal of modules in it) do (should) not affect the funtionality of the inbuild switch. This is a trade off that you have to accept if you use the inbuild switch of the ET200S (or other PN devices with inbuild switches). There really is no such thing as a linear bus topology anymore with Profinet and while "daisy chaining"PN Slaves by their inbuild switches may look like a linear structure it doesin fact constitute acascading of switches. One solution to your "problem" is to feed all Slaves from the same power supply as the CPU, this does not help though if you have to physically replace a faulty PN Slave (which will break the Ethernet bus unlike Profibus where the bus is looped through the plug) Another solution would be to useexternal Ethernet switches and make sure their power supply is "safe" (i.e. feed them from the same power supply as the CPU). This way you can remove individual PN Slaves. I hope this helps |
Cheers |
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