Technical Features; Linear Encoder; Limit Switches; Reference Switch - PI M-687.UN User Manual

3 Product Description
3.6

Technical Features

3.6.1

Linear Encoder

The M-687.UN is equipped with one optical linear encoder per axis. For the encoder resolution,
refer to the table in the "Specifications" section (p. 37).
Optical linear encoders measure the actual position directly (direct metrology). Therefore,
errors occurring in the drivetrain such as nonlinearity, backlash or elastic deformation, cannot
influence the measurement of the position.
3.6.2

Limit Switches

The M-687.UN is equipped with noncontact, Hall effect limit switches.
Each limit switch sends an overrun signal on a dedicated line to the controller. The controller
then stops the motion. If the controller does not stop the motion in time, the XY stage runs into
the hard stop.
Refer to "Limit Switch Specifications" (p. 38) for more information.
3.6.3

Reference Switch

The M-687.UN is equipped with one direction-sensing reference switch per axis. The switch is
located at about the midpoint of the travel range. This sensor transmits a TTL signal that
indicates whether the axis is on the positive or negative side of the reference switch.
Refer to the controller user manual and/or associated software manuals for the commands that
make use of the reference point signal.
Refer to "Reference Switch Specifications" (p. 38) for more information.
12 Version: 1.3.0 MP100E M-687.UN XY Stage