Error -1073807330 and -1073807331 in RS-485 Transceiver Control.vi (CFW-11 Inverter Communication Issue)

[MarcusP.]

Hello NI Community,

I’m facing an issue with RS-485 communication using a USB-RS-485 converter to communicate with a CFW-11 inverter through LabVIEW. I've been struggling with Error -1073807330 and Error -1073807331 when configuring the transceiver control in RS-485 Half-Duplex mode.

Here are the details:

System Setup:

• Device: CFW-11 Inverter (RS-485 2-wire communication)
• LabVIEW: Version 21
• Driver: NI-VISA, communicating through a USB-RS-485 converter
• Protocol: Modbus-RTU
• Goal: Establish communication to control the inverter and send commands like start/stop, speed reference, etc.

Issue Description:

I’m consistently encountering the following errors:

• Error -1073807330: VISA (Hex 0xBFFF001E) - "The specified state of the attribute is not valid, or is not supported as defined by the resource."
• Error -1073807331: VISA (Hex 0xBFFF001D) - "The specified attribute is not defined or supported by the referenced resource."

What I’ve Tried So Far:

1. RS-485 Mode Selection:

   • Tested all available modes: Wire4, Wire2-EchoDTR, Wire2-CtrlDTR, and Wire2-Auto. Based on the inverter’s configuration, Wire2-Auto should be the correct one, as it is a half-duplex 2-wire communication without the need for DTR control.

2. VISA Settings:

   • Configured the baud rate, parity, stop bits, and data bits as specified in the CFW-11 manual.
   • Flow Control: Set to none, as the inverter doesn’t require RTS/CTS or DTR/DSR control signals.
   • Termination Character: Disabled, since Modbus-RTU uses time intervals to mark the end of messages, rather than characters like \r\n.

3. Drivers:

   • Verified that the USB-RS-485 driver and NI-VISA are up to date.

4. Error Location:

   • The error occurs at the VISA Property Node in the RS-485 Transceiver Control.vi, specifically when setting the RS-485 mode and transceiver control attributes.

Questions:

• Is there a specific configuration or workaround to resolve these errors when using RS-485 Half-Duplex in LabVIEW?
• Could this be related to the USB-RS-485 converter driver, or is there a deeper VISA issue with attribute handling?
• Has anyone successfully established communication with the CFW-11 or similar inverters using Modbus-RTU via RS-485 in LabVIEW? Any specific configuration tips would be greatly appreciated!

Additional Info:

• I've already disabled attributes like DTR/RTS control and tested with a range of configurations, but no luck so far.
• The converter seems to function correctly in other basic serial applications, so I’m leaning towards a specific configuration issue in LabVIEW.

I gonna add the manual 

Thank you in advance for your help!