Table Of Contents

Timing Considerations for FieldDAQ

Last Modified: April 18, 2018

Sampling Rate Considerations

For the FD-11613 and FD-11614, if the sampling rate of a hardware-timed acquisition exceeds the maximum sampling rate of the module, the most recently acquired sample may be read multiple times and no warning or error is generated. Exceeding the maximum sampling rate of other devices in the same task generates warnings or errors. The first sample of a hardware-timed acquisition with these devices is sampled when the task is committed. Software-timed acquisitions with these devices always wait for a new sample to be acquired.

The FD-11601, FD-11603, and FD-11637 have a user-selectable sample clock timebase. You can set the sample clock timebase with the SampClk.Timebase.Src attribute/property. The FD-11601, FD-11603, and FD-11637 also have both a maximum and a minimum sampling rate. Refer to your device documentation to determine the sampling rate range and the user-selectable timebase for your FieldDAQ device.

On-Demand Timing

The FD-11601, FD-11603, and FD-11637 do not support the on-demand timing type.

Configurable Timing for FD-11613 and FD-11614

The FD-11613 and FD-11614 support the following timing modes:

High Resolution Optimizes accuracy and noise and rejects power line frequencies.
Best 50 Hz Rejection Optimizes 50 Hz noise rejection.
Best 60 Hz Rejection Optimizes 60 Hz noise rejection.
High Speed Optimizes sample rate and signal bandwidth.
Automatic Uses the most appropriate supported timing mode based on the Sample Clock Rate.

Use the AI.ADCTimingMode attribute/property to configure timing on the FD-11613 and FD-11614. This attribute/property is set by default to Automatic, which causes the module to sample with the highest resolution timing mode that is faster than the rate you specified.

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