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Modbus RTU over USB-RS 485 converter to control Parker AC10

Hi All,

I am trying to Start/Stop & frequency control Parker AC10 drive over RS485. I am using USB - RS485 converter. From what I have done so far, I think the issue is either my understanding of commands or the converter cable is not doing it properly.

  1. I validated USB-RS485 drivers are installed properly, by "Validate" button at NI MAX. It recognizes the converter as COM4. 
  2. I connected 120ohms at yellow(2) & Orange (5) then,  Data-, Data+, GND wires to B-, A+ and GND of AC10 RS485 connector, respectively.
  3. I set following parameters according to AC10 manual
    • F900: Address = 1
    • F901: Mode = 2(RTU)
    • F902: Stop bit = 1
    • F903: parity = None
    • F904: Baud rate = 3 (9600)
  4. I made sure same settings on VISA Test panel available at NI MAX and also opened I/O trace application for verification.
  5. As specified in section 12-10 of the manual, I entered 01062000000143CA expecting to run motor forward. The data write is correct according to I/O trace but AC10 drive doesn't act on the command.

I really appreciate if someone can give help on this. 


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I can't see any error in your post. Some manufacturers of RS-485 devices reverse the data names. So you can try to swap the data wires.



I never use the MAX I/O panel Just tried it. How do you enter hex data ??


Do you use LabVIEW ??



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Hi Kees,

thanks for your response.

I use MAX because it seems more user friendly than PuTTY or any other termianal apps.

Also it has the NI I/O trace where you can monitor raw data at the port. If you go to second icon on top "Input/Output", you can type in the second box from top named "Select or Enter Command"


I tried swapping the wires but no luck.


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Still not clear for me how you enter HEX data. Will give it a try one if the coming days.


Do you use LABVIEW ?

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