Universal Motion Controller, High Performance, 8-axis, Ethernet

The XPS has a 40 digital input and 40 digital output to read external switches, control valves or other digital devices and 8 analog Inputs and 8 analog outputs to precisely monitor any motion axis (such as position, velocity or acceleration). To synchronize external devices during a motion process, the XPS has dedicated "event and action" API's which users can use to trigger an action upon the occurrence of an event. Typical examples include sending a digital output when constant velocity is reached or initiating a TCL script when the motion is done. Once defined, the XPS autonomously monitors the status of the event to trigger the action with a latency of less than 100 µs! This powerful feature does not require any complex programming by the user and does not consume any time of the host PC or communication link since processing is done at the controller level. The XPS can be used as a master controller for a complete application.

Based on the TCP/IP Internet communication protocol, the XPS controller can utilize up to 80 virtual communication ports, known as sockets. Users can split their application into segments that run independently on different threads or even on different computers. Another practical advantage for many laboratory users is that sockets allow them to concurrently share the same controller for different applications. For example, it is possible for one group to use one axis of the XPS controller for an optical delay line while another group simultaneously uses the other axes for a totally different application. Both applications can run independently without any delays or cross-talk.

In the example below, a thread on socket 1 commands an XY stage to move to certain positions to take pictures while another thread on socket 2, independent of socket 1, concurrently manages an auto-focusing system.

TCL scripts can be quickly generated then executed directly from the XPS GUI Terminal for rapid development for motion programs. TCL stands for Tool Command Language and is an open-source string-based command language. TCL is field-proven, very well documented and has many tutorials, applications, tools and books publicly available at www.tcl.tk

XPS-D works in real time for up to 4 axes with one PCO connector. It generates pulses by comparing actual encoder feedback position with a set of predefined value within <35ns. The fast compensated PCO takes in account various mapping and compensations to fire trigger pulses at the desired positions within 5ns accuracy and frequency up to 1.6 MHz. 

When an ESP-compatible stage is connected to the XPS, the stage is quickly recognized and operating parameters are configured without the need for user inputs. This Plug and Play feature is not only transparent to the user, but it also ensures the safe operation of the stage.

The XPS incorporates pre-configured motion groups and user-definable motion groups to optimize the performance and simplify the use of advanced features like line-arc trajectories, splines, contouring, and complex PVT trajectories. These motion groups can be single axis positioners, spindles, gantry groups, XY groups, XYZ groups or multiple axis groups. The flexibility of grouping stages greatly improves process flow and error handling and provides a uniform structure for easy application development.

An extensive set of compensation features are available to the user including backlash, linear error and error mapping in single, 2D, or 3D. All compensations are corrected dynamically at each servo cycle, updated at the rate of 20 kHz. This broad selection of options transforms the most basic positioner into a high performance device; thus increasing the accuracy and performance of any motion application culminating in more reliable results.

The Line-arc trajectory is a motion path defined by a combination of straight and curved segments (available only for positioners in XY groups) such that constant speed is maintained throughout the entire region of interest. Sequential execution of the lines-arc trajectories eliminates discontinuities. A dedicated function performs a precheck of the trajectory to ensure optimized and safe execution within the positioners' parameters. The spline trajectory executes a Catmull-Rom spline on an XYZ group, passing through user-specified points with 3rd order polynomial segments at a constant speed. Similar to Line-arc trajectory, spline trajectory has functions for trajectory prechecking. The PVT-mode is the most flexible mode for creating complex trajectories. In PVT, a trajectory element is defined by the end position (P) and end speed (V) of each positioner plus the duration for the element (T). The controller then calculates the cubic function trajectory that will pass through all defined positions at the defined times and velocities. PVT is a powerful tool for any kind of trajectory with varying speeds and for trajectories with nonlinear motion devices.