Another thing that can cause the stepper motor to miss steps is
to run it at certain frequencies that are resonant to the motor.
If you write a program that increases the speed of the stepper motor
gradually you will find that at certain step rates the motor will be skip
or make a noise, this is normal. The effect is worse with some motors, and
loading and room temperature can make a difference.

------ John

> Hi Kris,
> I have tried with increased pulsewidth.  Still there is missing of steps.
> I am also observing some jerks at  some rotations.
>
> thanks
> rams
>
>
>
>                     Kris Wilk
>                     <wilk@REEFNET.        To:     PICLIST@MITVMA.MIT.EDU
>                     ON.CA>                cc:
>                     Sent by: pic          Subject:     Re: Stepper motor missing steps
>                     microcontrolle
>                     r discussion
>                     list
>                     <PICLIST@MITVM
>                     A.MIT.EDU>
>
>
>                     03/16/00 11:13
>                     AM
>                     Please respond
>                     to pic
>                     microcontrolle
>                     r discussion
>                     list
>
>
>
>
>
>
> The first two things I can think of are:
>
> 1) Pulses may be too short/rapid.
> 2) If the motor is under moderate load it can easily miss steps. Steppers
> are not generally powerhouses.
>
> Kris
>
> At 12:24 AM 3/16/00 , you wrote:
> >Hi Everyone,
> >      Anyone know for what all reasons a stepper motor can miss steps?  I
> am
> >driving a stepper motor using PIC 16c74 and I am moving it by 40 deg.  But
> >after 16 x 40 deg (i.e after giving 16 , 40 deg rotations), I am missing
> 40
> >deg.   How can I position accurately my stepper.  Is it related to the
> >pulsewidth?
> >
> >Thanks and regards
> >rams
>


          -----  John P. Brown      J.P.Brown@bradford.ac.uk ----
           \            --- Witty remark goes here ---         /
            --------------------------------------------------