'Waiting for Target to Respond' Periodic Error When Running an Real-Time VI From a LabVIEW Project

Updated Jul 20, 2026

Reported In

Hardware

  • CompactRIO Controller
  • PXI Controller
  • Industrial Controller
  • CompactDAQ Controller

Software

  • LabVIEW

Operating System

  • LabVIEW Real-Time (NI Linux Real-Time)
  • Phar Lap
  • VxWorks

Issue Details

 I am getting periodic 'Waiting for the target (<Real-Time target>) to respond' pop-up windows, as shown below, when my Real-Time (RT) target is connected to my LabVIEW project and under the following situations:

  • Running a VI on my RT target from LabVIEW
  • Exploring the LabVIEW project
  • Editing/Creating a VI
  • Simultaneously debugging five or more subVIs within the main application.

error.png

 

Solution

This behavior could happen due to several reasons: 

  • This can be caused by a network bottleneck that is preventing communication between the RT target and the PC running the VI. Please test with a direct USB connection (if available) or a direct Ethernet connection.
  • Another reason could be a misconfigured SMTP server code on the VI. Please confirm that the IP addresses are correctly set.
  • The thread responsible for communication between the development PC and the RT target may become starved if the code running on the controller consumes most of the available resources or if multiple subVIs that are part of the main application are being debugged simultaneously. Verify that CPU usage does not exceed 75%. If the issue occurs only while debugging, try limiting the number of subVIs being debugged at the same time to two or three.

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