9401 Module output, voltages goes from 0 to 5 V and ouput has delay?

[DJMILLER]

I am sending out a PWM wave out of the 9401 module generated by comparing a sawtooth and a sinewave with a greater than block. The output of the comparison on an oscilloscope shows the voltage going from 0 to 5V. Is there anyway I could decrease this value to go from -1 to 1? Is this possible because with my ouput now I would expect it to go from 0 to 1. Could you help me undestand this module better and any solutions to adjust my ouput voltage to go from -1 to 1?

Thanks,

Dane  

[dansch]

Hi Dane,

The NI-9401 module is an 8-Channel, TTL Digital Input/Output Module. This means that it can only output TTL signals, which will always be 0 to 5 V. Unfortunately, you will not be able to adjust the output voltage to anything else, unless you were to implement some kind of external signal conditioning. Another option, though far more difficult to implement for your application, would be to perform some software processing and output an analog output signal rather than a digital signal. This would, however, still require the use of a different module such as an NI-9263. Hope this helps,

[DJMILLER]

That does help, I was hoping to shift the voltage to -2.5 to 2.5 that doesn't seem like it will work. An external circuit will have to do the job. I can't use the 9263 because of the frequency restrictions and it slows down my loop by 421 ticks. My PWM signal needs to go around 300KHz.

Thanks,

Dane Miller