Hello Everyone,
I am building autofocus on the Nikon TE2000-E and having some problem controlling its z drive. I use serial port with the commands in the sdk to communicate with the microscope (through Labview). Whenever i sent a single-step (50nm) movement command to the motor (for example, SUC 1), 50% of the time it moved more than one step, sometimes even as large as 6 steps. It doesn't seem to be a closed-loop operation. Although I could correct for the movement with multiple commands, the imaging plane was drifting. Has anyone else encountered such a problem? I am not sure how does PFS work with such a motor. Thanks in advance! Yihan |
Stephen Cody-2 |
Dear Yihan,
How are you observing this focus drift? Is the reported position of the z-drive from the optical encoder in the TE2000-E problematic? Or are you observing an apparently larger step judging by the image in the microscope / computer screen?
Cheers
Stephen Cody
2009/2/17 Yihan Lin <[hidden email]> Hello Everyone, -- Stephen H. Cody Consulting Microscopist |
Hi Stephen,
Thanks for the reply. Yes, the readout position of the z motor was not what it is supposed to be and the image of the sample drifted obviously while z was moving. Best, Yihan Stephen Cody wrote: > Dear Yihan, > > How are you observing this focus drift? Is the reported position of > the z-drive from the optical encoder in the TE2000-E problematic? Or > are you observing an apparently larger step judging by the image in > the microscope / computer screen? > > Cheers > > Stephen Cody > > 2009/2/17 Yihan Lin <[hidden email] <mailto:[hidden email]>> > > Hello Everyone, > > I am building autofocus on the Nikon TE2000-E and having some > problem controlling its z drive. I use serial port with the > commands in the sdk to communicate with the microscope (through > Labview). Whenever i sent a single-step (50nm) movement command to > the motor (for example, SUC 1), 50% of the time it moved more than > one step, sometimes even as large as 6 steps. It doesn't seem to > be a closed-loop operation. Although I could correct for the > movement with multiple commands, the imaging plane was drifting. > Has anyone else encountered such a problem? I am not sure how > does PFS work with such a motor. > > Thanks in advance! > > Yihan > > > > > -- > Stephen H. Cody > Consulting Microscopist |
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