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485 Send Echo

Greetings,

When communicating with RS485 serial devices on Axcent 3 serial ports, the strings sent echo back on the receive even though 485 is enabled via the SET_BAUD command.

This does not occur on Netlinx serial ports when 485 is enabled. Is there something that I am missing to prevent the echo on Axcent 3 ports?

Thanks!

Comments

  • DarksideDarkside Posts: 345
    TT,

    Does this still occur if you remove the field cabling? (particularly from the device end)

    I don't believe I've seen this before and am wondering if there is a wiring issue here perhaps...

    Just a thought - you may have done it already!
  • Not sure about the AXcentIII's, but when I was using RS485 with the AXC-232 cards and the cardframes, I would send the command "EON" to prevent the echo of the characters.
  • TurnipTruckTurnipTruck Posts: 1,485
    Does this still occur if you remove the field cabling? (particularly from the device end)

    The echo occurs because the send and receive pairs at the Axcent 3 are tied together as they have to be for 485. Disconnecting the device end still shows the echo, just not the return data which appears after the echo.
  • Afaik only NetLinx will do 485 echo filtering, and the AXcess hardware never did.
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