Setting the Transceiver Wire Mode of Ports on NI Serial Boards

• How can I set the transceiver wire mode of ports on my NI serial boards?
• I have a device with a RS-485 port. How do I configure the transceiver mode in NI Measurement & Automation Explorer (MAX)?

You can set the Wire Mode property through NI MAX or LabVIEW. For details on the different wire modes you can set, refer to Transceiver Modes on NI-485 Serial Cards.

Note: If using a CompactRIO (cRIO) device, refer to Configure Wire Mode for RS-485 on a cRIO instead.

MAX

This option allows you to set the wire mode in MAX first before any application development.

1. Ensure you have administrator privileges on your computer account.
2. Search for NI MAX in the Start Menu and right click >> Run as Administrator. 
3. Expand Devices and Interfaces and select the RS-485 serial port of interest.
4. Select the Advanced tab at the bottom of the window. 
5. Select the desired wire mode from the Transceiver Mode drop-down menu.
   • 4 Wire is also known a Full-Duplex, which allows for simultaneous bi-directional communication.
   • 2 Wire is also known as Half-Duplex, which switches between transmitting and receiving over a single connection.
   • Refer to Duplex Architectures for further information.

LabVIEW

The Wire Mode property can be set programmatically using LabVIEW property nodes, which allows you to integrate this functionality directly into your code.

Refer to the shipping example RS-485 Transceiver Control.vi located in LabVIEW Help >> Find Examples >> Hardware Input and Output >> Serial, or follow the steps below to incorporate the property node into your application. 

1. Add a VISA property node on your block diagram. 
2. Wire the VISA serial session of the port of interest to the reference input. Alternatively, you can right-click on the reference input, create a constant or control, and select the port of interest. 
3. Select Property >> Serial Settings >> Wire Mode to configure the property.  
4. Right-click and select Change All to Write to set the property node to write.
5. Right-click on the Wire Mode input to create a constant or control. Refer to Serial Settings: Wire Mode to see the values it can take on.

Additional Information

The NI-VISA driver exposes the Wire Mode property in MAX and LabVIEW. If you are experiencing issues getting to the serial settings or do not see the correct serial port, refer to Serial COM Ports Missing in MAX or LabVIEW.

If you are having trouble accessing the advanced settings in a real-time target, try reinstalling the VISA driver.