MicroE Systems® Mercury II 60000 pages

Linear Encoders

Piezo LEGS® linear motors are capable of extreme
resolution, down to the sub-nanometer range. Position
encoders are required to build a system with high
repeatability and accuracy.
PiezoMotor offers linear encoders from Renishaw and
from MicroE Systems. Both companies are supplying
very high quality, top of the line encoders. Encoders of
two different resolutions from each company are kept in
stock at PiezoMotor. They are offered as an add-on to
the motor purchase, complete with cables, instructions,
drawings and CAD files, giving the customer an easy
integration. Common features to all encoders:

•t Non-contact optical encoders
•t Quadrature interface – A/B and index
•t Compatible with all PiezoMotor
microstepping drivers
Selection

With high resolution motors it is important to exercise
great care in selecting the appropriate encoder, and
even more important – the correct encoder location. The
rule of thumb is to place the encoder as close as possible
to the point of interest. This will minimize issues like
thermal drift in the mechanical structure. Experts at
PiezoMotor are available regarding design and selection
questions.

System design

To make a complete closed loop motion system a number
of key components are required:

•t
•t
•t
•t
•t
•t

Piezo LEGS® linear motor
Piezo LEGS® microstep driver
Linear guide (roller bearing)
Encoder
Scale, with/without index mark
Cabling

Installation Guideline

In a closed loop system, the motor, encoder and driver
act together to move an object to a given target position.
Accuracy of the position is given by the accuracy of the
sensor. With the high resolution motor, Piezo LEGS®, it
is possible to regulate to a position within ±1 sensor
count. The total system accuracy is depending on where
the sensor is mounted, how it is mounted and of course
the mechanical stability and thermal behavior of the
complete assembly.