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???
01/09/08 15:14
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 		 #149190 - GND loop wont be a problem
Responding to: ???'s previous message
Jeroen Wilbers said:
Domotica is a mix of the words Domus (house in latin) and electronica. It is a system to control whatever in your house.
In this case it is a complex audio system with multiple user interfaces and multiple playing devices and amplifiers.

The length of teh wires is some 50m between each unit. And several of the units have their own ground (PC, TV, etc). that's why I don't want to share a common ground. I think it will lead to ground loops.


Jeroen if you plan to use a twisted pair along with a GND conductor there wont be any GND loop problem as your power supply is already isolated. You worry unnecessarily for such short distance . The transformer you show on the RS485 side may be a representation only , but would require chokes to balance the signal also Termination resistance are required.

BTW why dont you opt for FSK modem ? if you plan to send audio signals.

AP




List of 27 messages in thread
TopicAuthorDate
galvanic isolated communication            01/01/70 00:00      
   What is domotica?            01/01/70 00:00      
      Domotica            01/01/70 00:00      
         GND loop wont be a problem            01/01/70 00:00      
            Misunderstanding?            01/01/70 00:00      
               RS485 Isolators            01/01/70 00:00      
      Transformers vs. optocouples ?            01/01/70 00:00      
         there are galvanically isolated 485 transcievers            01/01/70 00:00      
   PROFIBUS?            01/01/70 00:00      
      I would not            01/01/70 00:00      
         Have you seen...            01/01/70 00:00      
            no, I have not and I definitely would not            01/01/70 00:00      
         RS485            01/01/70 00:00      
   Fibre optics?            01/01/70 00:00      
      Yes, there is, but rather expensive!            01/01/70 00:00      
   Wireless?            01/01/70 00:00      
   Power-line communication?            01/01/70 00:00      
   Standard Radio Uses Optoisolators            01/01/70 00:00      
      Shield            01/01/70 00:00      
         noibody said not to ground cases etc            01/01/70 00:00      
   Isolated RS485            01/01/70 00:00      
   Jeroen, where are you??            01/01/70 00:00      
      please do not answer Jeroen, where are you??            01/01/70 00:00      
         ???            01/01/70 00:00      
            Kai            01/01/70 00:00      
               But he did already!            01/01/70 00:00      
   galvanic insulaton            01/01/70 00:00      

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