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DI Sample Clock Signal

  NI 6115/6120, NI 6122/6123, and NI 6132/6133 only

Use the DI Sample Clock (di/SampleClock) signal to sample the P0.<0..7> terminals and store the result in the DI waveform acquisition FIFO. Because there is no dedicated internal clock for timed digital operations, you can use an external signal or one of several internal signals as the DI Sample Clock. You can correlate digital and analog samples in time by choosing the same signal as the source of the DI Sample Clock, AI Sample Clock, or DO Sample Clock.

If the DAQ device receives a di/SampleClock when the FIFO is full, the DAQ device reports an overflow error to the host software.

Using an Internal Source

To use di/SampleClock with an internal source, specify the signal source and the polarity of the signal. The source can be any of the following signals:

  • AI Sample Clock
  • AO Sample Clock (NI 6115/6120 only)
  • Counter 0 Out

Program the DAQ device to sample the DIO terminals on the rising edge or falling edge of di/SampleClock.

Using an External Source

You can use a signal connected to any RTSI <0..6> pin as the source of di/SampleClock. You can sample data on the rising or falling edge of di/SampleClock.

Any PFI line that can be routed to RTSI can also be used as the clock source. Refer to Device Routing in MAX in the NI-DAQmx Help for more information.

You must ensure that the time between two active edges of the di/SampleClock is not too short. If the time is too short, the DI waveform generation FIFO is not able to store the sample fast enough.