The PZU-2000 has been specifically designed to provide a high resolution, and highly repeatable, means of controlling the X, Y, and Z position of an upright microscope's stage. The XY axes derive their precise control through the use of closed-loop DC servomotors employing high-resolution rotary encoders for positioning feedback. Optional linear encoders improve repeatability to less than 300 nm (typical) compared to the standard rotary encoder's 700 nm (typical) repeatability rating.

By using closed-loop control for the stage position, there is no chance that the stage will become lost, as can occur with open-loop micro-stepped stages after a number of moves and direction changes. The XY stage utilizes crossed-roller slides, high-precision lead screws, and zero-backlash miniature geared DC servomotors for smooth and accurate motion. The top plate of the stage accepts standard K-size stage inserts that are available for any sample, i.e., slides, Petri dishes, multiwell microplates, etc. The stage insert is moved in the Z-axis via a piezo element with a range of 100 µm with nanometer accuracy. By moving the sample in the Z-plane, any objective can be used, eliminating twisting wires or needed spacers as required when a piezo element is put onto a single objective. The microprocessor-controlled MS-2000 control unit provides for RS-232 and USB communication with a host computer for control of the XYZ axis.

The longer travel PZU-2175 model incorporates 175 micron piezo elements in the Z plate for nearly twice the vertical Z-axis travel as a regular PZU-2000. All other specifications and dimensions remain the same.

• Closed-loop control of the X, Y, and Z-axes for precise positioning and highly repeatable focusing
• Wide dynamic speed range with adjustable trapezoidal move profiles
• Smooth adjustable dual-range joystick control
• Backlit LCD display shows X, Y, and Z coordinates
• "Zero" and "Home" button for simple stand-alone operations
• Compact ergonomic tabletop control unit size is 6"D x 9"W x 3"H (9 x 23 x 16½ cm)
• Proven operation with many popular software packages

Previously, available standard piezo elements had to be mounted to a single microscope objective to obtain nanometer-scale movement in the Z-plane. In contrast, the PZU-2000 moves the entire specimen in the Z-plane. This offers several important advantages:

• By moving the entire sample in the Z-plane, any objective can be used instead of only the single objective with mounted piezo.
• The PZU-2000 eliminates the twisting of wires that create failures within objective-mounted piezo systems.
• No spacers are required on any objectives with the PZU-2000. Spacers are required with objective-mounted piezo systems, however, this added distance interferes with proper DIC operation. The PZU-2000 allows unhindered DIC operation on all supported microscopes.
• The PZU-2000's 100 micron (and the PZU-2175's 175 micron) limited travel range of the piezo element can be compensated by adding ASI's focus controller to the fine focus shaft of the microscope. This precision closed-loop DC servo motor drive can position the sample anywhere within the microscope's range of focus. From there the piezo element of the PZU-2000 can be used for ultra-fast nanometer positioning.
• The PZU-2000 offers all of the advantages of a piezo focusing system with none of the drawbacks.