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???
08/05/11 18:34
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#183225 - Hints...
Responding to: ???'s previous message
- Use slew rate limited RS485 drivers, if possible!!! They should also be ESD-tolerant at the line inputs.

- Use twisted pair for the RS485-lines. Do only twist "A" with "B", but not "A" with "GND" and "B" with "GND"!

- Do also transmit "GND" in the cable connecting the different RS485 partners. All RS485 partners must have the same signal ground! Connect the "GND" line at both ends to the circuit's signal ground.

- In RS232 cables twist "TXD" with "GND" and "RXD" with "GND". Connect all "GND" lines at both ends to the circuit's signal ground. Do not let hang any "GND" line "in the air"!

- If you use shielded cables, do it like the PROFIBUS people: Connect the shield at both ends to the earthed metal chassis or any other stuff that is connected to protective earth. But do not directly connect signal ground ("GND") to the shield. Do it via 10nF/1kV cap, right where the cable enters the metal chassis.

Kai Klaas

List of 29 messages in thread
TopicAuthorDate
Problem with RS232/RS485 converter...            01/01/70 00:00      
   More info please            01/01/70 00:00      
      probably            01/01/70 00:00      
   more info...            01/01/70 00:00      
      yes,i think            01/01/70 00:00      
         input impedance            01/01/70 00:00      
            i'm wrong            01/01/70 00:00      
               what is the right value?            01/01/70 00:00      
                  did You tryed capacitor?            01/01/70 00:00      
                     thanks...            01/01/70 00:00      
                     it works...!            01/01/70 00:00      
                        congrats            01/01/70 00:00      
                           shape            01/01/70 00:00      
                              dont            01/01/70 00:00      
                                 It is OK.            01/01/70 00:00      
   Hints...            01/01/70 00:00      
      schema            01/01/70 00:00      
         Repair...            01/01/70 00:00      
            transils...            01/01/70 00:00      
               RS485            01/01/70 00:00      
                  Sample Schematic            01/01/70 00:00      
                     Thank you very much for the schema...            01/01/70 00:00      
               AVX varistors...            01/01/70 00:00      
                  capacitor            01/01/70 00:00      
                     capacitors...            01/01/70 00:00      
                        GNDs            01/01/70 00:00      
                           1992            01/01/70 00:00      
                              Thanks...            01/01/70 00:00      
                                 Links...            01/01/70 00:00      

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