ORIC
®
Piezo Stage Controller PDXC
Chapter 3: Overview
Page 4
CTN015391-D02
backward. The slider does not move due to its inertia and the low coefficient of kinetic friction between the friction
element and the bottom surface of the slider. Figure 3.2.1 shows the piezo drive voltage during one "stick-slip"
cycle.
Repeating this cycle produces continuous forward travel of the slider. To travel in the reverse direction, the
opposite drive voltage pattern is required, resulting in rapid piezo expansion and slower piezo contraction, or "slip-
stick". During operation, the stage makes a high-pitched noise and may generate some heat. This is normal
behavior in the performance of the device and does not indicate a faulty condition.
Due to several factors that include the application conditions, piezo hysteresis, component variance, and the axial
load, the achieved step size will vary and is not repeatable. To help overcome this variance and accurately control
the stage movement, an external feedback system is added for closed-loop control of the feedback slider position
to controller.
Figure 3.2.1 Sawtooth Waveform Figure 3.2.2 Stick-Slip Movement Illustration
3.3 Stages Connection and Accessories
Figure 3.3.1 shows how the stages are connected to the PDXC controller. The two SMC connectors connect to
ORIC
®
Piezoelectric Inertia Drive Stages, i.e., PD1(/M). The DB15 connector connects with the ORIC
®
Piezoelectric
Inertia Drive Stages with Optical Encoders, i.e. PDX1(/M). Please note that the controller operates open- and
closed-loop stages separately under different operation modes. To switch operation modes, a power cycle is
required.
