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CEO: Dr. Bernt Götz • Phone +493641/66880 • Fax +493641/668866 • www.piezosystem.com
8 How to operate the digital amplifier NV200/D NET
8.1 Introduction
The digital amplifier NV200/D NET is designed to control the D-actuators from piezosystem jena. It
can be used with actuators with or without integrated position sensor. Actuators with integrated
position sensor allows positioning without creeping or hysteresis by digital PID loop control. The
amplifier can be controlled by USB, Ethernet, SPI or analog voltage input and reaches a resolution of
16 bits. piezosystem jena supports driver for Windows® operating systems.
The integrated digital loop controller comes as PID controller, additionally a slew rate limiter, a low
pass filter of 4
th
order for set point filtering and a notch filter are available.
The digital amplifier
NV200/D NET
allows the interchangeability from D-actuators and amplifier. All
needed information is stored on the ID-chip, located in act
uator’s connector, and will be read
automatically by the piezo controller after system start.
The actuator is connected to the
NV200/D NET
using the “PIEZO” plug. After switch on, the device
runs a self-test procedure, while the indicator LED is lightning red. This takes about 3 s. During this
step the controller reads the system specific parameters from the actuators ID-chip and sets up the
controller. If no actuator is connected, the LED stays red.
After the self-test, the actuator moves to its initial position. In case of open loop mode to the desired
voltage, in case of closed loop mode it moves to the set position.
In OL mode, the actuator is directly controlled by a voltage between -20
V and +180
V, however it will
be automatically limited to the admissible voltage range of the connected actuator. The reachable
stroke (pos. 1 to pos. 4) in unloaded condition can be seen on the actuator’s calibration protocol. The
stroke vs. voltage relationship is non-linear, shows hysteresis and creep and is affected by the
actuators load condition. The stroke decreases by higher stiffness loads. To reach a defined position,
actuators with integrated position sensors are used. They will have a smaller stroke in CL mode, the
remaining stroke, compared to OL mode is used as a reserve to reach the end positions (pos. 2 and
pos. 3) also under load.
