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Discover, Configure, and Communicate with NI 987x Modules in Scan Mode

Updated Oct 16, 2019

Reported In


  • NI-9870
  • NI-9871


  • LabVIEW Base


  • NI-Serial
  • NI CompactRIO
  • NI-RIO

Issue Details

I am trying to use my NI 9870 and NI 9871 modules in Scan Mode on my cRIO. When I expand the module in my project, I do not see the ports and I cannot modify the settings for the ports. How do I discover, configure, and communicate with the serial ports of my NI 9870 or NI 9871 modules?


You have to install NI-Serial 9870 and 9871 Scan Engine Support on your Real-Time controller by using a custom software installation. This can be done in NI Measurement and Automation Explorer (MAX) by the following steps:

  1. Expand your Real-Time Target under Remote Systems, right-clicking Software, and selecting Add/Remove Software.
  2. Choose Custom Software Installation and click Next.
  3. In the Custom software installation window, select the NI-Serial 9870 and 9871 Scan Engine Support.
  1. Click Next to start the installation.
  2. After the NI-Serial 9870 and 9871 Scan Engine Support is installed, create a LabVIEW project and add your CompactRIO target with NI 987x module underneath the Chassis.
  3. Ensure that the chassis is configured to be in Scan Interface mode by right-clicking it and selecting Properties.
  4. If your CompactRIO is correctly configured, right-click on your controller in the Project Explorer window and select Deploy All.
  1. Now the ports of the NI 987x will appear in Measurement & Automation Explorer underneath the RIO target corresponding to your CompactRIO chassis, as shown below.
  1. Once your ports are detected properly in MAX, they need to be configured to match the settings of the device you are communicating with. Configure the baud rate, parity, and flow control to ensure proper data communication. 
  2. In LabVIEW, place a VISA Configure Serial Port VI or a VISA Property Node to configure the settings of your individual ports.
  1. If the ports have been configured, you can open a VISA session for those ports and write to/read from them to communicate with your serial instrument.

Additional Information

Scan Mode for NI 9870 and NI 9871 modules is supported by NI-RIO 3.6 and NI-Serial 3.7 when used with LabVIEW 2010 and later.