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Revision as of 16:00, 24 October 2013 by Arthuredelstein (Talk | contribs)

ASI Stage

Summary:Controls ASI XY, Z stages and CRIF
Author:Jizhen Zhao, based on Nenad Amodaj's Prior adapter. CRIF and AZ100 Turret by Nico Stuurman. Currently maintained by Nico Stuurman
Platforms:All platforms (uses serial port)
Devices:XYStage, ZStage, CRIF, AZ100 Turret
Example Config File:None

Controls ASI's [1] XY, Z stages and the reflection-based CRIF autofocussing unit. Each device (XY stage, Z stage and CRIF) needs to be assigned to a serial port (even though all devices might actually be attached to one and the same controller and this controller is attached to the PC through a serial cable).

The ASI controller can control two different Z stages, a normal one ("Z"), and a piezo Z stage which can either be called "Z", or - if a normal motorized S stage is installed "F". AS of Micro-Manager version 1.2.7, you can instantiate multiple ASI Z-stages, which will take a pre-initialization property 'Axis' that can be set to either "Z" or "F" (do not instantiate the same axis twice!).

The piezo Z stage can be set up to receive trigger signals from many cameras (see documentation on Micro-Manager's Hardware-based_synchronization feature). A BNC cable is connected from the camera's TTL output to the piezo controller's trigger input. By synchronizing Z slices with camera exposures, you can acquire very fast Z stacks. By default, triggered Z stacks are limited to 50 slices: if you want to acquire Z stacks with more slices, please contact ASI directly for a firmware update.

The logic of the CRIF is a bit funky. The CRIF [2] cycles through a number of states (laser idle, laser on, calibrate, lock/unlock, laser off) by pressing the middle button on the controller for 6 seconds (see the CRIF manual [3]). Some of these state changes are implemented in the CRIF adapter. In general, it is best to first calibrate the CRIF by hand and then let the software lock and unlock the CRIF.

AS of ASI controller version 8.0 (called the 'WK Whizkid'), the build-in USB connection is actually a USB to serial converter. You can find Windows drivers for this converter at the ASI website and drivers for Mac OS X and linux at the silabs website.

The ASI-branded version of the driver does not work with all versions of Windows. Use the Silicon labs driver version 6.3 or higher instead.

The dipswitches on the back now control the baudrate settings for both the real serial and the USBto serial ports on the controller.

The following properties are currently implemented in the Micro-Manager ASI stage adapter:

Stepsize (for X and Y in um) Read-only property.
WaitCycles Sets how long the controller will wait after reaching a position before clearing its 'busy' signal. Number equals the number of 'servo' cycles (80 ms per cycle on XYstage, 120 ms per cycle on XYZ stages, etc..). Range: 0-255
Speed (for both X and Y)Sets the maximum speed at which the stage will move in mm/sec. Hardware maximum is 7.5 mm/s for 6.5 mm pitch leadscrews
Backlash (for both X and Y, in mm)Makes the controller approach the target always from the same direction, starting the set number of mm away from the target position
Error (for both X and Y, in nm)When the difference between the current position (as read from the encoders) is larger than this number, the controller will re-engage the motors to reach the target position
Finish Error (for both X and Y in nm)This setting controls at what difference between the target and current position the controller will stop trying to get closer to the target. Similar to Error, but this one applies to ongoing movements.
OverShoot (for both X and Y)Inverse of Backlash. Setting this might help to increase stability of the stage after a movement
MotorOnOff (for both X and Y) Switches motor On or Off.
NrMoveRepetition Number of times the stage sill approach the same position. Setting this to 0 will cause one approach. Settings this to 2 or 3 can increase the accuracy with which a position is reached.

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