Hi all,
Short version:
==========
does anyone know how to change EMC 2.2.6 to generate a longer "step" pulse
on parallel port?
I have tried changing both step time and step space, but they don't affect
the pulse width at all.
Long version:
==========
I am using a step motor kit from Keling. It came with their DB25 break out
board which has opto-couplers. I ran into the following problem in stepconf:
1. only X-axis works, the other two do not move
2. connect Y- and Z- motors to X- driver shows these two motors run just fine
with the X- driver
3. swap X- and Y- drivers, now neither X- nor Y- works
4. swap X- and Y- drivers back to original configuration, oops it's not working
any more
5. manually step the driver (by disconnect the step input from BOB, and then
touch 5V-GND-5V-GND,, ...), all drivers and motors are fine
After this, I brought the hardware to a place with oscilloscope, and found the
following:
1. the pulse width of "step signal" (pin 2 on parallel port) driven by EMC2 is
always 5-7us, no matter what's the step width I entered into stepconf
2. the optical coupler input has clean negative pulses with 5-7us width, but
the output is not moving
3. measure the "direction" output at the opto-coupler (which chnages between 0V
to 5V every couple seconds) shows that the rise and fall time is almost 10-us
So, I conclude the problem is that the opto-coupler is too slow to respond to
the 7us pulse. I was lucky in the beginning that X-axis worked for a short
time.
The problem can be solved by increasing the pulse width to >20us. But I just
can't get that with stepconf. Does anyone know how?
Thanks a lot in advance.
HJ
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