I see your situation. I am assuming you have an A/D converter and the digital lines are connected to the digital lines of the 6014. Wald is correct in that the 6014 samples the digital lines through software. The problems with this is that the sampling is not predictable in period (sampling interval). The timing can usually be off by a couple ms (due to the OS, the application etc.). When you are sampling the digital lines every 1s, then being off by a couple of ms is such a low percentage of our sampling rate that it will seem like stable acquisition. However, as you speed up the sampling of your digital lines to 10ms for example, a couple ms of error due to the OS or the application software is like 20% of the sampling rate and this could greatly affect if your digital lines are acquiring the last value or the next value. Therefore, your digital input will give you incorrect values in a greater percentage of the samples. This will lead to a very choppy waveform.
I believe that the above is what is actually occuring in this case. The only way around this is to use the onboard A/D of the 6014 or to use a 653x board as Wald has suggested or using a S Series board that supports "timed" or correlated digital input. Anyway, hope that helps. Have a good day. Ron
