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 29 / 40
Phone +49 721 4846-0, fax +49 721 4846-1019, e-mail info@pi.ws, www.pi.ws
NEXACT Drive Weight
The NEXACT Drive Weight (ID 0x07011e00) parameter is only used for NEXACT® and PICMAWalk drives, i.e. if the
PiezoWalk Type parameter (ID 0x07011d00) is set to 2. NEXACT Drive Weight gives the ratio of the shearing
voltage amplitude to the clamping voltage amplitude. This ratio influences the feed caused by one step cycle, i.e.
the step size.
Fig. 18: Step size depending on NEXACT Drive Weight setting,
shown in nanostepping mode
INFORMATION
For NEXACT drives, the optimum value of the NEXACT Drive Weight parameter is about 4.75. It is not
recommended to change this value.
7.2.3 PiezoWalk® Linearization Parameters
Piezo actuators and hence also the piezo actuators of the piezo drive modules show hysteresis. This means that
the position displacement of the shearing components is not linear in relation to the voltage applied. Polynomial
linearization is used to correct the performance of the PiezoWalk® drive (PiezoWalk Forward Correction and
PiezoWalk backward correction parameters, see also Fig. 15 on p. 24).
7.2.4 Parameters for Closed-Loop Control
If full-step mode is selected for a PiezoWalk® drive, it is automatically switched to analog mode when the current
positions of all axes to which the drive is assigned are inside the settling window (given by the ON Target
Tolerance parameter, ID 0x07000900). Switching back to full-step mode is done automatically when one of the
shearing voltages for that PiezoWalk® drive reaches the given limit (Soft Voltage Low Limit, ID 0x0c000000, and
Soft Voltage High Limit, ID 0x0c000001). Therefore the ON Target Tolerance value must be smaller than the
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