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Locking to an External Time Reference

Last Modified: September 15, 2017

Describes how to wait until the module is locked to an external time reference before continuing the program.

Setting an External Time Reference
  1. Place a While Loop on the diagram.
  2. Place an niSync Properties on the diagram inside the While Loop.
  3. Select Timing» Time Reference» Is Time Reference Present as the first parameter of niSync Properties. This property returns True if the chosen time reference is detected.
  4. Add another parameter to niSync Properties and select Timing» Time Reference» Offset from Time Reference . This property returns the offset between the timing module and the external time reference.
  5. Determine whether or not the offset from the time reference is within an acceptable range for synchronization:
    1. Place Less? function on the diagram.
    2. Connect the Offset from Time Reference property to x of the Less? function.
    3. Wire a constant to y of the Less? function and set the value as needed to achieve the appropriate level of synchronization for your application. If you are setting GPS as the external time reference, you can achieve higher synchronization accuracy if you wait until the self-survey is complete before continuing. You can monitor the status of the self-survey using niSync Properties.
  6. Place the And function on the diagram.
  7. Wire x < y? of the Less? function to the first input of the And function and the value from Is Time Reference Present? to the second input.
  8. Wire the output of the And function to the conditional terminal. The conditional terminal automatically stops the While Loop when a time reference is present and when the offset is less than the value you set for y of the Less? function.
You created a program that sets the external time reference for the timing and synchronization module, and then waits until the module is synchronized with the time reference before continuing.

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