Follow the guidelines below to avoid introducing timing uncertainty into AI node, AO Node, DO Node, and Set Output Data method calls. Failing to follow these guidelines may result in lost data points for DO Node calls or Set Output Data method calls when either of them are made from inside a single-cycle Timed Loop.

  • Use a single I/O Node to access AI and AO operations to ensure proper sequencing.
  • Do not run the Set Output Enable method when an AI, AO, or DO subsystems is active.
  • Do not perform the following operations concurrently:
    • AI Node call
    • AO Node call
    • Set Output Enable method call
    • Automatic line direction change when a DO call is made under the following conditions:
      • The call is made from outside of a single-cycle Timed Loop.
      • The Allow programmatic DIO line direction checkbox is enabled in the C Series Module Properties dialog box.
      • The DIO channel is configured as an input at the time when the DO node is called.

For an example of the recommended way to use the AI, AO , and DIO subsystems, refer to the NI 9381 Advanced IO VI in the labview\examples\CompactRIO\Module Specific\NI 9381\NI 9381 Advanced IO\NI 9381 Advanced IO.lvproj.