How to output Duty-Controlled Square Wave ?

[ControlEngineer]

Hello all , I need your help for solving my problem

I used the "Square Waveform.vi" tool to generate a square wave and have ability to control its duty cycle

Every thing is ok , but i want to ask how i can output this signal using 6024E-DAQ so that i can use it to

control a servo motor ..

i know it is very easy to use analog output , but i want to use a digital one .. is this possible ? how?

i tried to use "analog to digital" to convert the signal into digital form befor taking it on the output port ,, but useless attempt

Please , any one can help

thank you any way

yours ,,,

[Neville D]

QUOTE(ControlEngineer @ Apr 17 2007, 02:27 PM)

i know it is very easy to use analog output , but i want to use a digital one .. is this possible ? how?

Whats the problem with using an analog output?

Neville.

[James N]

Search the Help>Find Examples in LabVIEW. Check under "Hardware Input and Output". Look for an example like "Gen Dig Pulse Train-Continuous.vi"

There plenty of examples that do almost exactly what you're looking for.. if not exactly!

-James

FYI: "LAVA > Resources > Bug Lists > LabVIEW 8 Buglist" was probably not the right forum for this question..

[ControlEngineer]

Hello

Thank you Neville , i dont want to use analog outputs because i dont have enough channels

to control more than two motors at the same moment

[Neville D]

QUOTE(ControlEngineer @ Apr 17 2007, 10:11 PM)

Hello

Thank you Neville , i dont want to use analog outputs because i dont have enough channels

to control more than two motors at the same moment

AAAhhh..!!! You should have stated this earlier. I suspect you will be able to control AT MOST 2 motors with a single DAQ card. The reason is that each card has only 1 FIFO and if you are dynamically going to be changing the frequency and or the Output value using hardware timed IO, you will be able to do it for at most one output channel.

I think you will need to use counters for the pwm and not the digital outputs. You are limited to two counters and may even need both for one pwm. Sorry I haven't used DAQmx in a while, but its going to be difficult to control a whole bunch of pwms with a single DAQ card.

Just build a little "Analog Voltage in->PWM out" circuit and control via the analog output.

Neville.