Timing Engines

The PXIe-4468 provide four timing engines, two for analog input and two for analog output. Multiple timing engines allow those devices to run up to two analog input and two analog output tasks simultaneously, each using independent timing and triggering configurations.

By default, NI-DAQmx automatically selects an available timing engine when reserving the task. Use the DAQmx Timing attribute/property SampTimingEngine to specify the timing engine to use or to determine which timing engine NI-DAQmx automatically selected.

Note You must reserve the task before querying the timing engine unless you explicitly specified the timing engine.

The SampTimingEngine attribute/property is an integer value corresponding to one of the four analog input timing or analog output engines available on the device:

SampTimingEngine Value Timing Engine Used
0 te0
1 te1
2 te2
3 te3

The Sample Clock and Sample Clock Timebase, as well as the Start and Reference triggers, exist on each timing engine. Therefore, the names of the output terminals for those signals include the associated timing engine. If NI-DAQmx automatically selects the timing engine for a task, the timing engine, thus the output terminals for those signals, are undefined until you reserve the task. To reference one of those terminals, such as to share a Start Trigger across multiple tasks, use the Terminal attribute/property associated with each signal to determine the terminal name.

Note You must reserve the task before querying the terminal name unless you explicitly specify the timing engine.