ASI Stages and Z-drives Are Very Precise
ASI manufactures exceptionally precise motorized focus drives, XY stages, linear stages, and controllers. These devices can be utilized to obtain extremely accurate positioning for many applications including the automation of microscope focusing to obtain precise optical sections for sub-micron measurements, confocal microscopy, deconvolution, lineage analysis, 3-D reconstruction as well as any number of other microscopy applications. All of ASI's drives and stages employ a closed-loop positioning system where the command position is constantly monitored with a high-resolution encoder. We offer both shaft-mounted rotary encoders and stage-mounted linear encoders to provide feedback to the drive controller. The encoder feedback, along with the drive's mechanical design, insures precise positioning. The controller offers both remote control via front panel controls, as well as computer control via standard RS232 serial communication and USB. The control electronics continually monitors the stage position to sub-micron accuracy. Several unique electronic circuits and control algorithms, such as our copyrighted anti-backlash algorithm, are used to position the stage to obtain unsurpassed accuracy and repeatability.
There are three parts to successful micro-positioning. First, you need to know where you are and where you are going. Second, you need to be able to move in small enough increments to get exactly to the correct position. And third, you need a mechanical system that is stable and accurate. We accomplish the first part using feedback encoders with a resolution down to 20nm. Creating mechanical movement with nanometer resolution is more difficult, but we accomplish this with innovative high-torque motor control and micro-positioning firmware algorithms. Finally, our stages use precision-ground pre-loaded cross-roller bearings to insure mechanical accuracy.
If you are considering an Open-Loop Stepper System - think again.
ASI's closed-loop DC servo motor systems provide a number of key advantages over common stepper motor positioning systems
- Our drives and stages use geared D.C. servo-motors with position feedback from the focus shaft or leadscrew, or from a linear encoder. This means, unlike stepper motors, full torque is available even for very small movements. A closed-loop servo system does the positioning. The stage position displayed on the control console is the actual stage position, and is available for interrogation by a computer. (Open-loop stepper systems assume the stage is where the controller has told it to go and can get lost with repeated moves and direction changes.
- Our motor drives have lower electrical noise and lower mechanical vibration than stepper motor drives. This reduces the likelihood of interference with other research equipment. Unlike stepper motors that are driven by fast rise and fall time (electrically noisy) current pulses, our drive signals are D.C. and essentially zero when the drive is not moving. Our power supplies are linear rather than switching, insuring that they do not introduce electrical noise, and we shield our drive cables and power cords. Vibration is lower because the skew-wound D.C. servo motors we use, unlike stepper motors, do not have magnetic detents.
ASI characterizes its microscope stages as one of three types: upright, inverted, and large upright. Our MS-2000 line comprises our small upright and inverted stage models, whereas the MS-4000 was designed for large upright microscopes such as Leica's DMR-series, Nikon's E800 and 80i, Olympus' AX70, and Zeiss' Axioskops and Axioplans. We recommend the larger MS-4000 model when allowances for more clearance for objectives and condensers are warranted. For even larger stages, visit our MS-8000 page.
ASI offers many stage inserts to hold samples, specimens, and special items, including slides, Petri dishes, flasks, multiwell microplates, heaters, perfusers, etc.