RE: [CAD_CAM_EDM_DRO] SLA7062 Sync Mode (was New Article bla bla)

Hi,

I'm also a bit confused by the SLA7062 data sheet. All they say is that
noise is reduced when the unit enters sync mode. It doesn't really say what
sync mode does.

The way I reduce current in the ELS driver which uses LMD18245 is by
shifting the reference voltage from 5 volts to something like 1.25V. This
causes the motor current sensing circuits to start chopping at 0.75A instead
of 3A (when configured for full drive current).

The side effect of this is that the motor now becomes quite a bit noisier
since the chopping happens differently from the full power mode. The
LMD18245 is also a 'fixed off time' chopper.

The only other way to reduce current would be to change the current through
the individual windings to perhaps reduce one winding to 0 current and the
other to some low level that causes less noise. However, when I tried that,
(before using the 'reducing the reference voltage' approach), I found the
motor always moved so I gave that up.

John Dammeyer

> Keeping track of steps
> is a logic
> function, and is (or at least should be) unaffected by the
> PWM operation.
>