RE: Oatley Kit and power down.

>The stepper will NEVER jump just ONE step. In full-step mode, it
>could
>jump
>4 steps either way. Every 4 steps (in full step mode) the magnetic
>and
>current)

>polarities repeat. If there is enough mechanical torque on the motor
>from backlash,
>belt tension, weight, table friction, etc. it is possible that the
>motor
>may slip about
>2 full steps, and then it is a tossup which way it will go when
>power is
>reapplied.

>If the motor DOES jump just one step, that is an indication that
>interference from
>the relay switching is causing a pulse on the step input to the
>stepper
>driver.
>For this reason and others, you will probably need to use another
>relay
>and a
>capacitor charging series resistor to bring the power up slowly
>before
>the main
>power relay closes.

>Jon

Thanks for the reply Jon.
The steppers directly drive the leadscrew so I do not forsee a 4 step
movement, and simple power on off has now proved this.
But in the second possibility, I do see a problem, the first thing I
will try is better power supply isolation. Then your second relay
slow power up method.

Thanks again Pete.