PI PiezoWalk E-712 - Creep Reduction Procedure for NEXLINE Drives

User Manual
E712T0010, valid for E-712.N1, E-712.1AM, E-712.1AN, .2AN, .3AN
CMo, BRo, 10/31/2024
Physik Instrumente (PI) SE & Co. KG, Auf der Römerstraße 1, 76228 Karlsruhe, Germany page 15 / 40
Phone +49 721 4846-0, fax +49 721 4846-1019, e-mail info@pi.ws, www.pi.ws
4.3 Creep Reduction Procedure for NEXLINE® Drives
The iterative relax procedure ends in open-loop operation where the current position of the axis may drift over
time due to the creep of the piezo actuators in the NEXLINE® drive. Therefore, a creep reduction procedure can
be executed immediately after the end of the iterative relax procedure. The creep reduction procedure applies a
voltage sequence to the shearing segments of the NEXLINE® stack actuator pairs in analog mode and then sets
the shearing voltages back to 0 V (see Fig. 11 on p. 16). The voltage sequence for creep reduction procedure can
be configured using the following parameters:
 Anti Creep First Voltage (0x07012900) specifies the high voltage value to be applied during the creep
reduction procedure; default value is 220 V
 Anti Creep Second Voltage (0x07012a00) specifies the low voltage value to be applied during the creep
reduction procedure; default value is -30 V
 Anti Creep Voltage Slew Rate (0x07012b00) specifies the slew rate of the voltage during the creep
reduction procedure; in volts per second; default value is 22000.0 V/s. Note that the slew rate is specified
as an absolute value and valid for the positive and negative slope of the voltage.
 Anti Creep Sequence Enable Flag (0x07012c00) activates (1) or deactivates (0) the creep reduction
procedure; default value is 0
Fig. 10: Iterative relax procedure without creep reduction; target position (blue) and current position
(orange) of axis 1, piezo output voltage of channel 1 (pink). The axis position shows an unwanted
change over time due to the creep of the piezo actuators.