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attoMOTION
Encoder Options
precise closed loop control in any environment
Most of our positioners are available with optional encoders for closed
loop control. The encoder allows to read back the actual position, while
a feedback loops integrated into the corresponding electronics is used
to minimize the difference between target position and actual posi-
tion. Setpoints can either be defined in a software interface (ANC350,
ECC100) or on the front panel of the closed loop electronics (ANC350).
The available encoder types are described below.
/RES: Resistive Encoder
ANC350
0.1-2V
The working principle of this encoder type is based on a potentiometer. It is the method of choice
x
for applications at cryogenic temperatures, ultra high vacuum and highest magnetic fields (current
x V sensor
potential=
position
maximum field: 31 T). The /RES encoder measurement refers to the absolute sample position with a
resistive
element
GND
position resolution of 200 nm/0.1 m° and a repeatability of 1 µm/1 m°.
/NUM: Optoelectronic Encoder
The usage of a glass grating and the interpretation of the generated Moiré pattern characterizes
ANC350
the working principle of the /NUM encoder. The measurement refers to the relative sample position
with a position resolution of 1 nm/10 µ° and a repeatability of 50 nm/400 µ°. An absolute position
information is also available via a reference mark. This encoder option is suitable for ambient as
Grating
well as UHV conditions. The Premium Line/NUM models can also be used in high magnetic fields up
Optochip
to 7 T.
/FPS: Combination with Interferometer
Outstanding precision is achieved by combining attocube’s innovative, fiber-based interferometers
(FPS or IDS) with standard open loop positioning stages. A 25 pm position resolution and 2 nm repeatability even at cryogenic temperatures, UHV conditions and high magnetic fields outrivals the
specifications of any other encoder type. For detailed information on the interferometers, please
FPS
IDS
refer to the attoSENSORICS section on page 182.