NI 987x Module's COM Ports are Missing from Measurement & Automation Explorer

Updated May 26, 2020

Reported In


  • NI-9871
  • NI-9870


  • LabVIEW Real-Time Module
  • LabVIEW FPGA Module

Issue Details

I have installed the required software to use a NI 987x module on my CompactRIO, but the COM ports are not showing up under Serial & Parallel in the Devices & Interfaces for my CompactRIO. Why is that?


This issue can occur if the version of NI-VISA is different between the cRIO and the host PC. Matching these versions may cause the ports to appear in MAX and as VISA resources in your VI.

You should also consider to updgrade, or downgrade the firmware of your cRIO regarding the version of NI-VISA driver you have installed on your cRIO. The lowest is the version of the driver, the lowest should be the version of the firmware.

If this doesn't work, note that the NI 987x series modules are externally powered. If the external power is not connected the device will show under the Devices & Interfaces of your target, but the COM ports do not appear under Serial & Parallel. Apply external power, and restart the device.

If the device is powered, the next step depends on how your module is configured in the project explorer.
  • Scan Mode-If you are using the device is in scan mode then you must deploy the module.  In the Project Explorer, right-click on the c-series module, select Deploy.
  • Hybrid Mode-If you are using the device in hybrid mode, then you must compile your top level FPGA vi. Once compiled, you must run the compiled bitfile. You can do this with interactive mode, or by opening the reference inside of an Real Time VI. This FPGA VI can be simple, but a bitfile must be created that combines the scan mode functionality with your custom FPGA code.
  • FPGA Mode -If you are in FPGA mode, there is no way to see the ports in Measurement & Automation Explorer 

The COM ports should now enumerate under Serial & Parallel for your device.