Re: Microstepping thru the Tulips

Phil, I am confused by this as well. Take for example the SLA7062M
based stepper driver chip. This is a microstepping chip and it is a
chopper. With the limitted number of designs on hand that I have
using this chip, I have found the performance to be rather low
relative to what it should be. For example, two different driver
boards I have tested appear to be providing about 1/3 the amount of
torque at the motor than there should be.

Have you found the same problem with your SLA7062M drivers?

Chris




--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Phil Mattison"
<mattison20@...> wrote:

>
> Perhaps, but a 100KHz microstep rate and a 20KHz PWM frequency

implies that

> the coil current is modified five times in a single cycle of the

PWM, which

> is absurd. In that case, the PWM (or chopper, whatever) cannot

produce the

> power modulation that is supposed to be the big deal with

microstepping. Any

> microstep rate above the PWM frequency renders it meaningless.

What you end

> up with in practice is a single-step driver.
> --
> Phil Mattison
> http://www.ohmikron.com/