Why DurationInSeconds doesn't work?

Hello,

We are trying to use PCI6602 Daqboard to generate a serial of pulses to control servo. Our program is pretty simple like this:

    s=daq.createSession('ni');
    s.addCounterOutputChannel('Dev1','ctr0','PulseGeneration');
    ch1=s.Channels(1);
    for i=1:24
        ch1.DutyCycle=0.08+0.006*(i-1);
        s.DurationInSeconds=0.204;
        s.startForeground();
    end

It worked before. But these days, it seems like 's.DurationInSeconds' doesn't work. The signal generated by Daqboard is attached below. The duration time of signal sequence is much longer than 204 ms, which it suppose to be.

Anyone knows why?

Thanks

Answer 1

[Sruthi Ayloo]

I believe that the difference between s.DurationInSeconds and the actual duration of signal generation is a bug. The difference appears to be a constant offset approx 0.1s for MATLAB 7.14 (R2012a) and the offset is relatively more significant when the DurationInSeconds is small. This bug exists in MATLAB 8.3 (R2014a) as well. As a temporary workaround, you can adjust the DurationInSeconds accordingly.

[Jingyuan Dong]

I got the same answer from MATLAB support group too. We also tried MATLAB R2013a as well, the offset is about 0.2s.