Hi All,
I would like to update the PWM duty cycle value in a few ms but right now the best I get is roughly 17 ms; is that reasonable?
Is it possible to change the duty cycle for a PWM signal faster?
I am using the counter and hw timer. I am using a high resolution timer to measure the time. My conclusion is that it is the task.start() method that takes roughly 17 ms; is it possible to do it faster?
My setup:
Visual Studio 2005 / C#
Measurement Studio 2010
NI USB-6211
Here is the code
private String hwCounter = "Dev1/ctr0";
public void start(double dutyCycle)
{
if (state == STATE_GENERATING_PWM)
stop();
try
{
pwmTask = new Task();
pwmTask.COChannels.CreatePulseChannelFrequency(hwCounter,"PWM Channel", COPulseFrequencyUnits.Hertz,
idleState, 0.0,frequency,dutyCycle);
pwmTask.Control(TaskAction.Verify);
//Measure time
hiResTimer.Start();
pwmTask.Start(); // This takes 17 ms, Why?
hiResTimer.Stop();
Console.WriteLine("Duration: {0} sec\n", hiResTimer.Elapsed);
state = STATE_GENERATING_PWM;
}
catch (Exception exception)
{
MessageBox.Show(exception.Message);
pwmTask.Dispose();
}
}
public void stop()
{
if (state == STATE_IDLE)
return;
pwmTask.Stop();
pwmTask.Dispose();
state = STATE_IDLE;
}
Kind regards,
Suru
