The XPS universal motion controller is a high performance, 8 axis machine that can drive a variety of motor types and execute complex motion through high speed Ethernet TCP/IP interface. Aside from its outstanding servo rate and triggering, the XPS is user friendly with its intuitive GUI and straightforward driver card installation. Because of its features, the XPS is suitable for both research and industrial applications.
The XPS incorporates pre-configured motion groups which can be user-definable 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. This 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 8 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 XPS features variable PIDs that automatically adjust their values proportional to the distance from final position. This unique feature can tighten the gain loop when in position or close to final position while loosening the gain during motion to improve stability. Using variable PIDs also allows dedicated tuning of the servo behavior for short and long stroke motion resulting in improved motion sensitivity.
Based on QNX real-time operating system and multi-tasking functionality, the XPS is capable of executing complex, internally stored, user-generated applications using TCL scripts. The motion processor supports TCL program execution without adversely impacting higher-priority tasks. With this advanced real-time multi-tasking functionality, the XPS can not only manage the most complex motion requirements but also serve as a powerful, standalone process controller to concurrently support multiple applications.
The XPS features four channels of 14-Bit analog-to-digital converters which can be integrated with a motion process using a TCL script. The analog inputs can be converted to directly control the position or speed of a motion axis via external analog inputs. This is critical in precision alignment or auto-focusing routines which require real-time feedback from other devices including power meters, vision systems, or other sensors. Besides higher communication speed, the A-to-D conversion is internal to the XPS, therefore no processing burden is added to the host PC or the communication link. Consequently, this feature can improve process development and throughput.
In master slave mode, any motion axis can be electronically geared to a single master where all axes compensations of the master and slave(s) are taken into account. This mode simplifies complex system setups by synchronizing multiple motions into single axis commands.
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 safe and optimized execution for the connected 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. Similarly 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.
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 share the same controller for different applications concurrently. 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 other axes for a totally different application. Both applications can run independently without any delays or cross-talk.
The XPS has a total of 60 digital I/O's to read external switches, control valves or other digital devices and 4 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 occurence 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 from 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.
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.
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 (www.tcl.tk).
The XPS controller is capable of driving up to 8 axes of most Newport positioners with internal drivers that slide into the back of the mainframe. These factory-tested modules are powered by an internal 500 W power supply that is independent of the controller power supply.