Re: When do I need a step multiplayer ?

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "shadi_salhab_78"
<salhab@m...> wrote:

>
>
> Hi all ,
> A problem am facing in designing my new machine with a servo motors
> is that when do I need a step multiplayer ? I'm using 2:1 reduction
> pullies am I want 120 IPM feed . Is there an equation to know ? or
> just use a very fast computer?

////clipped from earlier post:

if the line count of the motor encoders times 4 (in
quadrature) times gear/belt/leadscrew reductions are greater than
your max pulses per second to move the target distance in that one
second.

Try this formula:
V1 = target speed = max speed in IPS
Pr = pulses/rev = Encoder line count * 4
Pi = pulses/inch = Pr * (belt-gear ratio) * (leadscrew pitch)

PPS = pulses per second needed from PC = V1 * Pi

IF PPS > 45,000 THEN implement step multiplication

The line count of the encoder is a very big factor here because you
have to supply four times the line count to rotate the motor one
revolution (Pr). Then you have to multiple that by any gear rations
like belt reduction or leadscrews (Pi). If you do all of that and
find you need 45,000 pps or less then you DON't need a step
multiplier. As you can see you need to have all of the numbers to
make an accurate prediction.


After you get to about 1G in computer speed a faster one does not
mean more pulses per second.