NPS3220 Queensgate 2-Channel Piezoelectric Controller w/ 2-Axis Nanopositioning Stage

The NPS3000 series closed loop controllers are the Next Generation of NanoPositioning systems from Queensgate. Designed specifically to control Queensgate's Nanometer Precision Mechanisms. Using state of the art digital signal processing technology the NPS3000 series combines piezo drive amplifiers, capacitance position sensing circuitry and servo control capability, providing reconfigurable control parameters. Use of PID (proportional integral differential) feedback terms greatly improves settle times and minimizes the effect of mechanical resonance. Advanced control techniques developed by Queensgate allow 21-Bit resolution (0.05 nm in 100 µm), more than 30 times better than previously available. The virtual front panel software facilitates user control of all operating parameters, including PID loop set up.


The Queensgate NanoControl Panel provides easy access to the NPS3000 command set. A picture of the controller's front panel, complete with live display of the stage positions and status LEDs, presents an intuitive means of setting up and monitoring the controller. Access to PID parameters is via slider bars; simply move a slider and the corresponding PID parameter will be instantly updated. Other parameters are grouped logically according to function. Changing a command parameter is simplicity itself, just enter the new value and click the mouse. The Queensgate NanoControl Panel also allows the complete set of command parameters to be saved to disk. This can be retrieved and downloaded to the controller in a matter of seconds. There is no limit to the number of parameter sets that can be stored to disk.


The snapshot mode of operation allows NanoMechanism responses and noise data to be recorded by the controller at the full system cycle rate (one sample every 40µs), for a limited period of time. This data can then be loaded to the host computer for display and analysis. The snapshot mode can be set up to generate a stimulus on any one of the 3 channels. This means that the response does not necessarily have to be measured for the same channel as that to which the stimulus is applied, and therefore allows inter-channel effects to be characterized. The NanoControl Panel displays snapshot images alongside the PID slider bars making it easy to adjust the settings and see the change in dynamic performance almost in real time, allowing PID adjustment optimization of dynamic response. On-screen cursors are provided to allow measurements to be made directly from the snapshot graph. Snapshot data can also be exported to disk for use with other packages such as a spreadsheet.


The NPS3000 command DLL provides the link between your Windows programming environment and the NPS3000 controller. It supports the entire command set, allowing you to control and monitor the controller through a series of easy-to-use function calls. The DLL supports both the RS232 serial interface and the NPS-PAR parallel interface. All you need to do is call the appropriate functions; the DLL takes care of the communications.


The controller command language is largely independent of the communications interface used, although there are some minor differences in the way the commands are transmitted. All transmissions between the host computer and controller (and vice versa) are 64 bits in length, providing fast communications, decode and response times. These comprise a 16-bit command word (or response word), a 32-bit data word and a 16-bit terminator. The data word can contain floating-point or integer format data, depending on the parameter concerned. Command and measured positions can be transmitted in either floating-point or integer format. For floating-point transfers, a choice of IEEE single-precision or TMS320C3X single-precision formats is provided. The command set includes the following functional groups:

Control loop mode (open/closed loop; freeze facility)
Command and measure positions
PID control parameters
Linearisation coefficients
Calibration parameters
Snapshot settings
General controller settings
LabView Drivers

Software support for the NPS3000 series controllers includes a set of Virtual Instruments (VI) drivers for LabView®. This means that you can develop your test application working entirely in LabView®'s 'G' graphical programming environment, so you don't have to write a line of code.

Typical applications requiring nanopositioning include: scanning probe microscopy, atomic force microscopy, interferometry, synchotrons (scanning stages for x-ray microscopy, beam focus and steering, prism and crystal alignment), disk drive read/write head testing, semiconductor test equipment, nanoidentification systems, beam steering systems, optical cavity tuning and modulation, optical alignment, image jitter correction, micromachining and nanomachining, force moment sensing, deformation monitoring, and most any other applications requiring nanometer positioniong.