digital pulse generation

[koon]

hey there, i am now trying to generate a simple pwm signal using digital write and read. so far, i've been trying to manipulate the square waveform and offset it so that it only goes from zero to one volts. den i would compare this analog output with a zero comparator whose output would be sent to NI-DIOwrite.this doesnt work at all. some help would be greatly appreciated. it would be best if there is a file that i can look into. thanks and regards

[Tomas_E]

Right now you are trying to capture a digital signal right?
First, connect the output of the comparator to a oscilloscope which can capture single pulse, thus test your comparator.
If the output is correct, connect it to NIDIO, also probe the voltage there, if the output is not correct, then the channel of that DIO might break down.
If the output is correct, it will be the problem of your software, or unluckily the NI card.