On 7/9/20 1:44 PM, andy pugh wrote:
On Thu, 9 Jul 2020 at 19:26, R C <cjv...@gmail.com> wrote:
The stepper motors I use with a stepper driver, those common DM542 ones,
the stepper motors themselves are 2A and 1.8 degrees per step.
...
As with PWM itself, I am probably just not too familiar with it.
Do you mean PWM?
yes
Stepper drivers take step and direction, not PWM.
correct, but the direction is either high or low, while the PUL (step)
ping/port takes PWM signals, which you can easily create with a RPI, I
have that part working. I have the impression that on the
stepperdriver, the pulswidth is constant a table in the docs shows that
, so the duty cycle is always 2.5us of power and then some delay so
if a cycle iis 2.5us hi, 2.5us low and then 5us low, the duty cycle is
10us at 50%.. and if hi is 2.5 us, the low is 2.5us, the duty cycle
is5us, at 100% etc.
That is what I wanted to ask, if that is correct.... because
typically you would set the input frequency, and that gives you a duty
cycle length, and the width of the pulse (plus the voltage) would
dictate the power. but with these drivers, the pule width seems
fixed ?? and the frequency can pretty much can be anything less then 200k
I think this is a job for an Arduino, rather than LinuxCNC.
Especially as I assume that an equatorial mount runs at an absolutely
constant rate anywhere in the world?
well, I am not using CNC (that is why I called it off topic) unless
anyone would ever like to build that into it... (instead of a mill and
lathe, add a telescope.. *lol* )... an Arduino wouldn't do anything
different than the RPI does. I can make the motor run at different
speeds etc.. just want to know the relation between dutu cycle and
pulse length ..
Ron
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