Dear Christophe

Have you ever tried switching off the stage? That should at least 
tell you whether the stage is moving actively (in which case the 
linear encoders are most likely to blame).

Beat

At 16:47 18-02-2009, you wrote:
>Dear all,
>
>I'm concerned about the XY stability of a motorized stage. It is a ASI
>MS-2000, equipped with XY linear encoders, controlled by Metamorph
>Software. Using a 100X objective and a 1.6 magnifying lens, and
>aquiring at a fixed position, I can get up to 1 micron drift over half
>an our. That is, the amplitude of movement is inside a 1 micron
>diameter circle, but the test bead can have a several micron
>trajectory inside this circle (up to 5 or 10 microns total movement).
>These are the worst cases, usually I have a few pixels drift (that is
>around 500 nm). This is
>
>Is that stability acceptable or should I have the stage serviced ?
>What can be the cause of instability (I'm already inside a big
>incubator box, on an optics air table, with all cables and wires
>coming from the ceiling...).
>
>Christophe Leterrier