Error -65512 Using CompactRIO in Scan Mode

Updated Oct 14, 2021

Reported In


  • CompactRIO Controller
  • CompactRIO Chassis


  • LabVIEW
  • LabVIEW Real-Time Module

Issue Details

  • I am running my cRIO in Scan Mode but I am encountering the -65512 error. I am concerned that this is effecting the accuracy of my data, how can I fix it?
  • I have a cRIO that uses scan engine only and at random times during boot up it throws scan engine fault -65512.



Try the following suggestions to resolve this error:
  1. Use a timed loop. Timed loops ensure that a loop executes at a defined speed; however, there performance varies depending upon the situation they are used in. Timed loops provide a high level of determinism however they are not as reliable as the second solution.
  1. Use a while loop, remove all timing components and instead ensure the while loop is synchronized to scan engine by using Synchronize to Scan Engine VI (Found in: Measurement I/O >> NI Scan Engine). This solution, while more reliable than the previous method, may not be accurate over longer periods of time - especially when using external clock sources such as a PTP or NTP Clock.
  1. Add the recommended Wait time of 30-60 seconds to the initialization sequence in the RT Main VI. 

Additional Information

Error -65512 is a common error seen while using a cRIO in Scan Mode and typically seen when the Real-Time (RT) time of a cRIO is changed. This often leads to issues with syncing multiple pieces of hardware, data loss occurring and the loss of determinism (reliability/accuracy of code).

This error can also occur because while the RT might finish its boot sequence, there are still critical processes that still have to start before RT Main can run. Scan engine may not have initialized in time for the first call.