EtherCat is becoming a communication standard in industrial automation. The continuous need for higher precision in R&D, test and manufacturing drives the demand for more high-performance, piezo-based nano-positioning and scanning systems; semiconductor manufacturing, optics and photonics are typical examples. PI (Physik Instrumente) now offers a EtherCat compatible version of its successful E-727 digital piezo controller family.
The piezo controller can be integrated into complex automation environments systems and operated as an “intelligent driver” for two- or three-axis piezo-based nanopositioning systems. PI also offers ACS based EtherCat motion controllers for long travel precision positioning stages such as used in laser machining and gantry systems for 3D printing.
Piezo controllers with digital servos provide advantages over traditional analog piezo controllers, such as higher bandwidth, linearity, and easy optimization of the servo parameters by software. The E-727 also provides two notch filters that help suppress mechanical resonances in high-speed operation of piezo-mechanisms yielding higher bandwidth. A sensor sampling frequency of 100kHz and servo update rate of 20kHz provide excellent performance with minimized noise. Intelligent servo algorithms minimize the settling times and allow repeatability into the subnanometer range.
Other advanced features of the digital piezo controller include 4th-order polynomial linearization for the piezo mechanics and control electronics, an integrated data recorder, an ID chip for fast and quick exchange of the system components, as well as subordinate, programmable drift compensation. In addition, there is the option of dynamic digital linearization. This DDL function lowers phase shift and trajectory errors to an indiscernible level in the case of dynamic-periodic applications. This is important for scanning applications that have to identify a particular position and reach it again accurately.
Like all PI motion controllers, the E-727 comes with extensive software support such as LabVIEW drivers and dynamic libraries for Windows and Linux. The E-727 can also be operated via TCP/IP or USB even without an EtherCAT master and commanded with PI GCS codes. Additional interfaces are SPI for fast serial transmission of position values to / from an SPI master, 4 digital I/O (each) and 4 optional high resolution analog I/O (20 bits) for external sensors, target values or external amplifiers.