Emerson Exchange 365

• Not Answered

Communication of AB micrologix 1400 plc to Deltav S series serial card

Hi

I have deltav ver 13 , SQ controller and I have s series serial card, configured for RTU , Master. On micrologix1400 end I have 1761-NET AIC+ serial to rs 485 converter and wiring is regular A, B and GND, A is connected to serial card terminal 10, B is connected to serial card terminal 12 and GND is connected to serial card terminal 9.

I added device in explorer but it is not communicating, when I try to diagnose it shows bad device and not communicating I have only 1 device connected serial card and distance is not more than 30 FT.

I tried with different baud rate but no luck.

my serial card LED light is off even though there is only one device in line.

below is screen shot of diagnostics.

please help me to solve this error.

 

ganesh jadhav

• 11 May 2018 8:15 PM
• Cancel

5 Replies

• foxriver

  

  • 11 May 2018 8:28 PM

  Hi Ganesh. You did not mention having a terminating resistor in wiring? Did you install one?
  
  Dave

  • Cancel
• ganesh jadhav

  

  • 11 May 2018 8:30 PM

  In reply to foxriver:

  I have 120 ohm installed at ML 1400 end

  • Cancel
• foxriver

  

  • 11 May 2018 8:43 PM

  In reply to ganesh jadhav:

  RS485 generally requires termination at both ends to prevent reflection. Sometimes the convertor has it built in. I am not familiar with the SQ serial card, but i have termination resistors across the terminals of my M series cards.

  • Cancel
• ganesh jadhav

  

  • 11 May 2018 9:20 PM

  In reply to foxriver:

  Hi Dave
  
  thanks for your reply.
  right now I don't have 120ohm resister with me so not able to connect it at deltav end.
  i have 220ohm resistor will it work?

  • Cancel
• foxriver

  

  • 12 May 2018 5:12 PM

  In reply to ganesh jadhav:

  Not sure if it will work or not, but I don't think it can hurt to try.

  • Cancel