Solution

This is a known issue with the NI 9220, NI 9222, and NI 9223 when using
DAQmx up to
9.7.5.
There are three ways to ressolve this issue:
Method 1Upgrade to
DAQmx 9.8 or later.
Method 2Explicitly set the timing engine for each task. Make sure to specify a different timing engine for each task. Valid values for the Timing Engine are 0, 1, and 2.
This can be achieved by using the DAQmx Timing property node and setting the
SampTimingEngine property as shown below:
Method 3
In C or C++, this can be achieved by using the DAQmxSetSampTimingEngine
function:
DAQmxSetSampTimingEngine (TaskHandle taskHandle, uInt32 data);
For Example:
DAQmxSetSampTimingEngine (analogTask1, 0);
DAQmxSetSampTimingEngine (analogTask2, 1);