How do I Connect to Ethernet Targets with Multiple Network Cards in the Host?

Updated Oct 17, 2022



  • LabVIEW 8.0.1 Full

I have an ethernet device that I am trying to find in Measurement & Automation Explorer (MAX).  My host computer has multiple Ethernet cards.  When I attempt to connect to my Ethernet device, such as a real-time target, it does not show up in MAX.  How can I access this device from MAX?

LabVIEW 2009 and after:
This behavior was changed for LabVIEW 2009.  Now National Instruments software will detect and connect to real-time devices and other remote targets using all of the network cards in the host machine. If you are using LabVIEW 2009 or later and are not seeing your ethernet device in MAX, refer to this general troubleshooting document .

Prior to LabVIEW 2009:
  • Disconnect everything from your first network port and then search for instruments in MAX. Your device should now be recognized. Plug all devices back into your first port.
  • Edit your default network interface by doing the following:
1. For Windows XP: Navigate to Control Panel»Network Connections»Advanced»Advanced Settings...

For Windows 7:  Navigate to Control Panel»Network and Internet»Network and Sharing Center»Change adapter settings»Advanced»Advanced Settings...
  You may need to press the Alt key in order to bring up the Advanced menu.

2. Press the Up and Down arrow to rearrange the adapters.  Move the real-time connection to the top of the list to make it default.  Click OK to apply the changes.
  • Disable the ethernet/network card that the instrument is not connected to.  Once a connection is established, the other ethernet/network card can be enabled without affecting the system.
  • Change the device's IP address to be higher than the others' so Windows will attempt to communicate with it first.

Additional Information

Prior to LabVIEW 2009, National Instruments software does not allow you to select which port MAX uses to connect to ethernet devices.  Therefore if you have multiple network cards in your computer, MAX may be attempting to use a card that your device is not connected to.

When trying to connect to a remote device using a Windows PC, the default for the OS is to try and communicate with the device having the highest IP address number first.