Error -89137 When Using NI-9403 for Simultaneous Digital Input and Output

Updated May 1, 2023

Reported In


  • NI-9403
  • C Series Digital Module


  • LabVIEW


  • NI-DAQmx

Issue Details

I have created two DAQmx tasks using an NI-9403 in my VI. In one task, I have configured some lines as Digital Inputs and in the other task, I have configured different lines as Digital Outputs. I am using Hardware Time for this application. However, when I try to run my code I get the following error:

Error -89137 occurred at DAQmx Start Task .vi:7220001

Possible reason (s):

Specified route cannot be specified, because it requires resources that are currently in use by another route.



This error is generated by DAQmx Start Task VI when you are trying to use serial modules as the NI-9403 for Hardware Timed Digital Input and Digital Output tasks simultaneously. All the digital lines of this module (and any other serial module) have to be set either as Digital Input or Digital Output at a time.

If you want to run both tasks simultaneously, using serial modules, you will need to use a Software Timed Task. If your application requires a Hardware Timed Task, you can use a parallel module as the NI-9401.

Additional Information

A complete list of serial and parallel digital modules can be found here.