Re: [CAD_CAM_EDM_DRO] Re: faster steppers

Alan,
Well, I didn't really measure the maximum steprate. I just turned the
frequency up (squarewave 50& dutycycle) 'till the motor stalls and then
looked at the scale on knob. Easy, but not really exact values.
There are a lot of programs available to measure frequency on the PC - most
for soundcard 'tho. Have a look at, for example:
http://w3.pca.net/~cpclark/SBTESTEQU.html
And you are right about the acceleration/deceleration ramps, see my previous
post.

/Henrik.

Alan wrote:

> How were you using a rate generator to MEASURE the maximum steprate?
> Just by feeding the driver with a square wave? I've been trying to use
> a Frequency counter designed for Amateur Radio (StarCraft?). Works part
> of the time, but I suspect that the pulses (20us) may be too short for
> higher speeds. I can read the frequency relatively well with an Interro
> "lab scope" made for automotive testing ;>) I've also read pulse
> repetitions with a 100mhz HP 'scope.
>
> Actually, as we have a good digital signal, one should be able to count
> the frequency with a program running on the PC, and using the parallel
> port as an input.
>
> You will need proper acceleration/deceleration ramps to get the maximum
> speeds. AND high P.S. to coil voltage ratios (for full current) for
> good "chopping".