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If your closed loop servo is oscillating it needs service...

Mark Cannell

Beat Ludin wrote:

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> http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal
>
> At 08:44 20.11.2003, you wrote:
>
>> Could there be any scattering of the beam while it is parked?
>
>
> I have a similar question: how stable is the position of the beam when
> its
> parked. I'm totally naive when it comes to galvo mirror control (i.e.
> I've
> never taken a closer look at how exactly it works) but I would expect the
> positioning to be a closed-loop system involving some sort of feedback
> mechanism. So systems like that can never stand completely still , i.e.
> they always oscillate around the set point. Could the amplitude of this
> oscillation be big enough to increase the apparent diameter of a "parked"
> beam? I really have no idea, but I guess there are people here who can
> answer this. Also, if there's some kind of electrical interference that
> might also introduce an oscillation. Just some additional hypotheses to
> explain the large apparent beam diameter...
>
> Beat