Error -66208 Using NI CompactRIO in Scan Mode

Updated May 8, 2024

Reported In

Software

  • LabVIEW

Driver

  • NI CompactRIO

Issue Details

  • I am running my cRIO in Scan Mode but I am receiving the following error.
Error -66208 occurred at Shared Variable

Possible reason(s):

LabVIEW: Invalid variable refnum. Either the variable was deleted after reference was opened or a valid reference was never opened.

This error or warning occurred while reading the following Shared Variable:
Error.PNG
  • When I try to read from my cRIO IO Variables, I see error -66208. How can I fix this?

Solution

Follow the troubleshooting steps below to resolve this error:
  1. Ensure that NI Scan Engine has been deployed.
    • In the LabVIEW project, expand the cRIO target and right-click on the Real-Time Scan Resource or the C Series Modules.
    • Select Deploy.
  2. Verify that NI Variable Engine and NI PSP Service are set to Automatic and Running.
    • Open the Services application from the Windows search bar.
    • Scroll down the list of services to locate NI Variable Engine and NI PSP Service.
    • If either service is not running, restart the service manually.
  3. Check whether the same error occurs in a new LabVIEW project with new IO Variables.
    • If cRIO IO Variables are removed or renamed, it can cause problems in the project.
  4. Repair the NI CompactRIO driver.

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