NI 6533 and 6534 devices provide two timing engines for digital I/O. Multiple timing engines allow those devices to run up to two tasks simultaneously, each using independent timing and triggering configurations. Also, each timing engine uses different lines for handshaking and burst handshaking.

By default, NI-DAQmx assigns a timing engine based on the ports used in the task. Refer to device documentation to determine which ports use which timing engine. Use the DAQmx Timing property/attribute SampTimingEngine to specify the timing engine to use or to determine which timing engine NI-DAQmx automatically selected.

The SampTimingEngine property/attribute is an integer value corresponding to one of the two timing engines available on the device:

On NI 6533 and 6534 devices, 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.