IMAQ1409: question on imgPulseCreate function.

[TNI]

In VC++, I used the following functions to generate some pulse.
errChk(imgSessionTriggerDrive(Sid,IMG_EXT_TRIG0,IMG_TRIG_POLAR_ACTIVEH,IMG_TRIG_DRIVE_UNASSERTED));
imgPulseRate(1000,500,&delay,&width,&timebases);
errChk(imgPulseCreat(timebases,delay,width,IMG_IMMEDIATE,IMG_TRIG_POLAR_ACTIVEH,IMG_EXT_TRIG0,IMG_PULSE_POLAR_ACTIVEH,PULSE_MODE_TRAIN,plsID));

But it always give me the error message:
invalide parameter #1.

What is wrong with the first parameter??

Thanks.

[TNI]

I also want to know,
1.whether the imgPulseCreate function generate a TTL signal or not, why I can not display it in the 0-5v range by oscilloscope?
2.PULSE_MODE_TRAIN, why it can not display continuous pulse?

[TNI]

Why I cann't generate continuous pulse by IMAQ1409?
Why the amplitude(value) of the pulse isn't correct?
Pls answer this question!