PI PiezoWalk E-712 - Page 25

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 25 / 40
Phone +49 721 4846-0, fax +49 721 4846-1019, e-mail info@pi.ws, www.pi.ws
Overview
With the minimum cycle time (t
Z_min
, given by the PiezoWalk Min Step Cycle Time parameter, ID 0x07011900) and
the step size per cycle (x
cycle
, given by the PiezoWalk Step Size parameter, ID 0x07011700), the maximum absolute
velocity of a PiezoWalk® drive is given.
min_
max
Z
cycle
t
x
v =
In open-loop operation, the maximum velocity can be limited by the PiezoWalk Open-Loop Velocity parameter (ID
0x07000204); in closed-loop operation by the VEL command (which concerns the Servo Loop Slew-Rate
parameter, ID 0x07000200).
The velocity furthermore depends on the following parameters:
 Nanostepping mode: PiezoWalk Clamp-Free Voltage (ID 0x07001900) which affects the duration of the
phase where the shearing components of one piezo actuator pair move back to the starting position.
 Full-step mode: PiezoWalk Shearing-To-Clamping Ratio (ID 0x07011800) which gives the ratio of the
clamping time (2 * t
c
) to the whole step cycle time t
z
 NEXACT® and PICMAWalk drives only (PiezoWalk Type (ID 0x07011d00) is set to 2): NEXACT Drive Weight
(ID 0x07011e00) which gives the ratio of the shearing voltage amplitude to the clamping voltage
amplitude
INFORMATION
If PiezoWalk® drives are moved at too high velocities, the high voltage output of the E-711/E-712 can be
deactivated due to internal overheating, or the maximum output power of the E-711/E-712 can be exceeded
so that the system is switched off automatically.
 Change the parameters for the PiezoWalk® drive performance only after careful consideration and be
aware that overheating of the E-711/E-712 system or overloading of its power supply is then your
responsibility.
PiezoWalk Step Size
The PiezoWalk Step Size (x
cycle
, parameter ID 0x07011700) is the feed caused by one step cycle, with maximum
amplitude of the shearing voltages (V
Dmax
– V
Dmin
).
Can be determined as follows for a PiezoWalk® drive if a sensor is present:
1. Select the driving mode via the PiezoWalk Driving Mode parameter (ID 0x07001a00).
2. Optionally: Limit the open-loop velocity via the PiezoWalk Open-Loop Velocity parameter (ID
0x07000204). Default: 100 µm/s.
3. Make a note of the current position (x
alt
) of the PiezoWalk® drive
4. Start 100 steps in positive direction by sending
OSM <PiezoWalkChanID> 100
5. Make a note of the current position (x
neu
) of the PiezoWalk® drive