A 2nd counter on a USB6008 using DIO's?

[newbie09]

hi,

Quick question is it possible to built code in Labview, that would act as a second counter, using digital I/O's?

I want to count the number of pulses for two difference pulse trains, and the use the number of pulses to determine the position of the 2 stepper motors?

Any help greatly appreciated!

Peter

[johnsold]

Peter,

You can certainly count pulses from a digital input line in software.  However, the DI lines on the USB6008 are software timed and have a fairly low update rate.  Without looking it up, I think the rate is ~100 Hz.  If your pulses can ever occur much faster that, you will miss pulses and lose track of your position.

Lynn 

[newbie09]

Lynn,

the slowest pulse train is 1.4ms? is this too fast for using the digital i/o? And if not where could i find an example of the code?

Cheers

Peter

[newbie09]

Lynn,

Its approx 700Hz, not good so?

[johnsold]

Peter,

1/1.4 ms = 714 Hz.  This is much faster than the software timed DI can manage.  You would lose too many pulses for this to be useful.

Lynn