I'm using the "AI Waveform Scan (waveform)" vi in Labview version 6.1 in combination with an NI 4552 DSA board to acquire and display 4 channels of data. Analog input is triggered using the "analog" trigger setting of the vi. Occassionally, (approx. one in 50 triggers) I've observed that the waveform data channels will erroneously swap, one becoming four, two becoming three. No error is reported by the vi, or by any of its sub vis. This swap doesn't occur if any other trigger type is selected. What is causing this swap?
