User Manual
E727T0005, valid for E-727
BRO, 2019-06-28
Physik Instrumente (PI) GmbH & Co. KG, Auf der Roemerstrasse 1, 76228 Karlsruhe, Germany Page 50 / 240
Phone +49 721 4846-0, Fax +49 721 4846-1019, Email info@pi.ws, www.pi.ws
NOTICE
Damage to piezo tip/tilt systems with differential drive!
PI piezo tip/tilt systems with differential drive, such as S-334 models, provide motion in two axes
(θ
X
, θ
Y
). The motion is controlled by axes 1 and 2 of the E-727. If a third axis is provided by the E-
727, it is only used to give access to the fixed voltage (100 V) that is required by the differential
drive. A piezo tip/tilt system with differential drive can be damaged by oscillations when the servo
mode is switched on for axis 3 of the E-727.
Do not switch on the servo mode for axis 3 of the E-727.
Make sure that the Power Up Servo On Enable parameter (ID 0x07000800) has the value 0
(= servo mode is not automatically switched on) for axis 3 of the E-727.
Changing the piezo output voltage too fast can cause damage to a piezo tip/tilt system with
differential drive.
Make sure that for axes 1, 2 and 3 of the E-727, the velocity for rising and falling of the piezo
output voltage in open-loop operation is limited to a suitable value. The velocity is given by
the Open Loop Slew-Rate parameter (ID 0x07000201). For axes 1 and 2, the parameter value
should be set to the axis travel range in µrad (e.g., 50000 (µrad/s) with S-334). For axis 3, the
parameter value should be set to 100 (= 100 V/s).
When the E-727 is not used but is to remain switched on to ensure the temperature stability, the
piezo output voltages should be set to 0 V to increase the lifetime of the piezo ceramics. When a
third axis is present in the E-727, zeroing and restoring the piezo output voltages in wrong order
can cause damage to a piezo tip/tilt system with differential drive.
1. Because zeroing/restoring the piezo output voltages will cause motion of axes 1 and 2, make
sure that the axes can move safely.
2. Proceed as follows for zeroing the piezo output voltages when the E-727 is not used but is to
remain switched on:
a. Switch off the servo mode for axes 1 and 2; corresponding command:
SVO 1 0 2 0
b. Set the piezo output voltage to 0 V for axes 1 and 2; corresponding command:
SVA 1 0 2 0
c. Wait 1 second, or check the piezo output voltages for channels 1 and 2 by sending:
VOL? 1 2
d. When the piezo output voltages for channels 1 and 2 are 0 V, set the fixed voltage to 0 V
by sending the corresponding command for axis 3:
SVA 3 0
3. Proceed as follows for restoring the piezo output voltages when the E-727 is still switched on
and the piezo tip/tilt system is to be used again:
a. Set to piezo output voltage to 100 V for axis 3; corresponding command:
SVA 3 100
b. Wait 1 second, or check the piezo output voltage for channel 3 by sending:
VOL? 3
c. Switch on the servo mode for axes 1 and 2; corresponding command:
.
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