Hello;
To have both tasks synchronized, you need to have the same pulse train clocking both tasks.
To accomplish that, you can have the digital clock line being routed through RTSI to be the AI Scan Start line. By doing that, you will have the same clock pulse train clocking both acquisitions. Then, when the digital acquisition starts, the analog input acquisition will start, and when the digital acquisition stops, the analog input will follow.
Hope this helps.
Filipe A.
Applications Engineer
National Instruments