Error 65539 Using FPGA I/O Nodes with NI 9202

Updated Sep 26, 2019

Reported In


  • NI-9202
  • CompactRIO Controller

Issue Details

I added an NI 9202 to my CompactRIO (cRIO) project and am trying to read values from it using an FPGA I/O Node. When I run my code, I get the following error:

Error 65539: The input function missed one or more data points. Make sure the loop can execute as fast as the module data rate.

Why am I getting this error? 


This error occurs when the loop calling the FPGA I/O Nodes is running too slowly, which results in an overrun error, as data was available more quickly than it is being read in the code. There are a few causes of this error that you can check in your code: 
  • Ensure you have set the data rate you expect for the NI 9202. You can do this programmatically using an FPGA I/O Property Node, or by right-clicking the NI 9202 module in your CompactRIO project and selecting Properties. Set your desired data rate and click OK
    • Checking the module properties and selecting OK also resolves the existing Known Issue 213378 , in which modules that have not been configured return data at an incorrect rate. See the Additional Information section for more on the Known Issue and potential workarounds.
  • If you are using multiple delta-sigma modules , ensure you separate modules running at different data rates into different loops. 
  • Reduce the complexity and execution time of the FPGA loop by utilizing parallel execution and pipelining.

Additional Information

Known Issue 213378 results in the module acquiring data at an incorrect rate that is faster than the module's maximum data rate. The data returned due to the Known Issue is invalid. The issue only occurs if you have newly added a module to your LabVIEW project without configuring the module or setting the data rate programmatically. To work around this issue you can do one of the following: