Click to Enlarge
The Rotation Stage with
Brackets Attached
Click to Enlarge
The Rotation Stage with no
Brackets Attached
Click to Enlarge
Features of the
Rotation Stage
Click to Enlarge
The Interface
Board
Click to Enlarge
Features of the
Interface Board
Homing the Rotation Stage
Positioning the Rotation Stage
Resonant Frequencies
Handling
The ELL8K(/M) rotation stage and interface board components are robust to general handling. To ensure reliable operation,
keep the surface of the plastic track contacted by the motors free of oils, dirt, and dust. It is not necessary to wear gloves
while handling the rotation stage, but avoid touching the track to keep it free of oils from fingerprints. If it is necessary to clean
the track, it may be wiped with isopropyl alcohol or mineral spirits (white spirit). Do not use acetone, as this solvent will
damage the plastic track.
The open frame format of the ELL8K(/M) can tolerate up to 8 kV of static discharge. ESD precautions should be taken, as an
electrostatic discharge can produce an electrical signal that may cause an unintended movement of the stage. A bending load
in excess of 500 g applied to the board may cause the PCB to deform, which will degrade the
performance of the rotation stage. As readings from a magnetic sensor are used during the
homing and positioning of the stage, avoid subjecting the structural PCB to excessive loads or
magnetic fields. Limit the strength of magnetic fields in proximity to the magnetic sensor to ±5
mT to avoid negatively affecting the homing and positioning operations.
Mounting and Loading the Rotation Stage
The ELL8(/M) rotation stage should be mounted so that the top surface of the stage is in the
horizontal plane. There are four Ø0.17" (Ø4.2 mm) through holes located along the edges of the board, which are visible in
the image at the center-right of this tab, that may be used to mount the stage with or without the mounting brackets. The
two brackets included in the ELL8K(/M) bundle have slots that accommodate 1/4"-20 (M6) cap screws to facilitate
mounting the stage to breadboards and optical tables. The brackets possess 6-32 (M3) tapped holes aligned with
the four through holes in the board. Attach the brackets on either side of the stage, as pictured at right, so that
they extend out from and span the left and right sides of the board. Do not attach the brackets so that they cross
the back of the board, as metal brackets in contact with the electronics may cause electrical shorts detrimental to
the operation of the stage. When mounting the stage, ensure that the installation does not bend the PCB.
Loads may be mounted to the stage using the 37 tapped holes for 8-32 (Imperial Version) or M4 (Metric Version) threaded screws, whose spacing is shown in
the diagram below and in the diagrams included in the
Specs
tab. The maximum allowed weight of the mounted components is 200 g. In all cases of mounting
and loading, ensure that nothing interferes with the moving parts of the rotation stage.
Supplying Power
When the setup includes the interface board, power may be supplied through the Micro-B USB connector and/or the 5 VDC power socket located on the
board. The electronics on the interface board convert the applied DC signal to a sinusoidal signal oscillating at the required resonance frequency.
The ELL8K(/M) bundles include a 5 VDC power supply whose connector mates with the power socket on the interface board. Delivering power through this
socket also leaves the Micro-B USB connector available to accept a USB cable connection to a computer, which can be used to control the stage remotely.
The power supplied by the computer through the USB 2.0 connection is not sufficient to power the stage. If computer control is not necessary, another option
for supplying power to the stage is a portable USB 5 V battery pack connected to the Micro-B USB connector on the interface board.
When the implementation does not include the interface board, the connection with the power source is made using the pins on the Picoflex connector that is
included on the rotation stage board. A pinout diagram of this connector is included in the
Pin Diagram
tab, and information on powering and addressing the
rotation stage is given in the manual and the communications protocol manual, respectively.
Operation of the Motors
The motion of the ELL8(/M) stage is controlled by forcing the piezoelectric elements to vibrate at specific ultrasonic frequencies. For each motor, there is one
ultrasonic resonant frequency that will push the stage forward, and another that will pull the stage backward. Operating a motor at one of its resonance
frequencies causes the tip of the motor to continuously cycle in a tight clockwise elliptical path. When the motor is driven at its other resonant frequency, the
tip of the motor cycles through that same path in a counterclockwise direction. Both resonant frequencies are around 100 kHz. The total displacement at the tip
of motor is a function of the mechanical load it is driving and the voltage supplied to the piezo element. In the case of no loading and a 5 V maximum driving
voltage at a resonant frequency, the tip of the motor expands and contracts no more than a few microns while tracing the elliptical path. Please see
The
Elliptec™ Motor
tab for more information and an animation illustrating the operational principle of the motors.
Homing the Rotation Stage
To Home the stage, press the BW button on the interface board, click the Home button in the Elliptec software's graphical user interface (GUI), or send the
