Re: stepper problem

Jon Elson <elson@p...> wrote:

> andrewyslee wrote:
>
> > What are the symtoms of a driver having step and direction signals
> > switched? Suppose the driver is commanded to move 10 pulse

clockwise.

> > So we have 10 pulses wrongly going to the direction terminal while
> > the step signal will be, say, +5V constant. This may explain
> > the "tingling" sound plus no motion?
>
> Could be. Due to the way software-generated step-direction signals

are

> created, almost anything could happen. If the software is careful

to never

> cause a transition on the DIR pin except when the direction

actually changes,

> then nothing should happen, not even 'tingling'. But, many

programs cause the

> direction pin to change between step pulses.
>
> > Now suppose the driver is now commanded to move 10 steps counter-
> > clockwise. Now the step signal will be 0 volt while we still have

10

> > pulses wrongly sent to the direction terminals of the Geckos.
> > Theoretically, we'll still have no motion plus perhaps
> > still "tingling" sound from the stepper?
>
> But, when you change direction, then the driver should see at least

one pulse

> on the dir pin as a step. Which way it goes is harder to

determine. But, if the

> software causes the dir signal to come and go in one direction, it

could cause

> the driver to only move in one direction. It should be easy to

switch the wires

> and see if the problem clears up.
>
> Jon

Ah!!! looks that there's still plenty learning to do!!!

The old geeeezer found the problem. Amazing what a USD10 multimeter
can do!!! The +5V cable insulation had not been trimmed off leaving
the connection open. Trimming the insulation off got the motors
humming along beautifully. But it means that leave us to puzzle over
how without the +5V the Geckos can produce 1 way motion (plus "soft
tingling noise") in the first place???