CompactRIO  and CompactRIO Single-Board  controllers provide eight timing engines for input and a separate eight timing engines for output. The eight input timing engines are shared between analog input, digital input, and NI 9361 tasks. Multiple input timing engines allow those chassis to run up to eight analog input, digital input, or NI 9361 tasks simultaneously, each using independent timing and triggering configurations.
The eight output timing engines are shared between analog output and digital output. Multiple output timing engines allow those chassis to run up to eight analog output or digital 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.
The SampTimingEngine attribute/property is an integer value corresponding to one of the eight timing engines available on the chassis:
|SampTimingEngine Value||Analog Input, Digital Input, and NI 9361 Timing Engine Used||Analog Output and Digital Output Timing Engine Used|
On the CompactRIO and CompactRIO Single-Board controllers, the Sample Clock and Sample Clock Timebase, as well as the Start, Reference (for analog input, digital input, and NI 9361 tasks only), and Pause 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.