Generating "instantaneous" voltage switch

[Thibault_Prevost]

Hi,

My question is fairly basic. I have been using an already existing vi from the NI example folder called "Cont Gen Voltage Wfm-Ext Clk" to output a square wave (voltage) to a motor. My problem now is the switch from +V to -V does not occur fast enough: typically the time required for it is ~10ms  and I would need it be 5-10 times smaller (ie 1-2ms). Is there a way for me to achieve this?

Thanks,

Thibault.

[RavensFan]

What data acquisition device are you using to output the voltage?  The rise or fall time is going to be dependent on the speed and quality of the card.

[Thibault_Prevost]

I am using an SC-2350 carrier.

[Dennis_Knutson]

Good for you. Now can you answer the question about the type of DAQ device you are using? And when you answer that, also provide information on what sample rate you've got it set to.

[Thibault_Prevost]

Sorry... the DAQ device I'm using is an NI DAQCard-6036E. As for the sampling rate, this will sound really stupid but I am not quite sure about what it actually is... You are talking about the rate at which the voltage signal is actually output to the motor (?). Is it something set in some of the built-in subvis (I have attached a pic of the block diagram I am using)?

[Dennis_Knutson]

It's displayed on your front panel. It also seems to be derived from the number of samples per buffer. Increase that.

[RT4CY]

Hi Thibault,

Does your application require external clocking?  If not, I would just use the Cont Gen Voltage Wfm-Int Clk shipping example.  If you want your +V to -V transition to take 1 ms, simply enter 500 Hz for your desired frequency.



Let me know if I have misunderstood your application.