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???
05/25/08 18:44
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#155101 - not with '176
Responding to: ???'s previous message
Maybe 1-resistor termination at segment's ends will be
better than 3-resistors termination. Data rate is slow (<=19,2kb/s).

If you use 1 resistor termination, you need "idle safe" transcievers, the '176 is not

Asuuming 6 devices, 50mA each - 2.4V drop on GNDx and 2.4V on Px. I think tranceivers will be still in safe region
You better check your statements or Ohms law
"6 nodes 100m apart"

6*50 = 300ma
8 ohms * 6 = 48 ohms
48 * 0.3 = 14.4V

Erik

List of 25 messages in thread
TopicAuthorDate
RS485 questions            01/01/70 00:00      
   Yes its required            01/01/70 00:00      
      +            01/01/70 00:00      
         you can not achieve isolation ....            01/01/70 00:00      
            +            01/01/70 00:00      
               why common power and isolated 485?            01/01/70 00:00      
         where to get supply            01/01/70 00:00      
            RS485 experiences            01/01/70 00:00      
               all the stuff inside            01/01/70 00:00      
                  Prifibus alike            01/01/70 00:00      
                     not with '176            01/01/70 00:00      
                        sn75lbc176 planed            01/01/70 00:00      
                           why galvanic isolation ?            01/01/70 00:00      
                              what is wrong?            01/01/70 00:00      
                                 then try MAX3158            01/01/70 00:00      
                                    how about this little gem?            01/01/70 00:00      
                                       have you read it fully            01/01/70 00:00      
                                          It's just another way to get the job done.            01/01/70 00:00      
                                             OK, I'll bend it in neon            01/01/70 00:00      
                     Prifibus alike ..... it isn't            01/01/70 00:00      
                        Galavanic isolation            01/01/70 00:00      
                           Galavanic isolation            01/01/70 00:00      
   Do it like Profibus            01/01/70 00:00      
   economical approach            01/01/70 00:00      
      Thanks for all answers!            01/01/70 00:00      

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