Re: Microstepping

Hi PJ,

A little more, in addition to what the others said.

The microstepping drive will control the current going to the two
different windings. It feeds the current to the A coil following a
sine wave (the B coil is 90 degres out of phase from the A)
For example:
u Ph Ph
Step A B
==== === ===
1 100 0
2 98.08 19.51
3 92.39 38.27
4 83.15 55.56
5 70.71 70.71
6 55.56 83.15
7 38.27 92.39
8 19.51 98.08
9 0 100

The numbers are the percent of full current sent to the coils. As
you can see at step 5, both coils are energized the same. At this
point, the motor consumes most current. The point of FULL step is
arbitrary. Traditional stepping would put FULL step at positions 1 &
9, while the 3 axis stepper driver I sell* considers position 5 be at
FULL step (both coils energized equally). Another 8 microsteps would
again place you at a FULL step.

Since the amount of magnetic 'pull' is based on the amount of current
flowing throught the coils, the rotor will 'follow' the point were
the most current is directing it, starting with A at step 1, and
ending at B in step 9. In step 10, (not shown), the cycle reverses
itself, but with the current in the A coil flowing in the REVERSE
direction as before (if the current caused the magnetics to 'PULL'
before, now it will 'PUSH'. 2 more cycles (steps 17-24 & 25-33) are
required to make a full cycle in the sine wave.

Hope that helps some.

Jeff
www.xylotex.com
*(XS-3525/8S-3 3 axis Stepper Driver)

--- In CAD_CAM_EDM_DRO@y..., "P. J. Hicks" <hickspj467@a...> wrote:
> Hi,
> Another newbie question.
>
> I see 'full step', 'half step', 'quarter step', and 'eighth step'
mentioned at various times. If the stepper motor moves for example,
1.8 deg/pulse (step) for each pulse (step) put out from the PC
parallel port how does the motor move 1/2 or 1/4 or 1/8 steps? Or
does it move 2, 4, or 8 steps? Or is the controller able to
manipulate the motor windings to get multiple steps OR partial steps
for each step output by the PC? Then how is the above effected by
parallel/series windings connection?
>
> Computer says move one step; does motor see 1, 2, 4, or 8 steps OR
sees 1, 1/2, 1/4, 1/8 step? How?
> PJH
>
> [Non-text portions of this message have been removed]