Chapter 5
Software Reference
Min Pos - the stage/actuator minimum position (typically zero).
Max Pos - the stage/actuator maximum position.
Pitch - the pitch of the motor lead screw (i.e. the distance travelled (in mm or degrees)
per revolution of the leadscrew).
Units - the ‘real world’ positioning units (mm or degrees).
Homing
When homing, a stage typically moves in the reverse direction, (i.e. towards the
reverse limit switch). The following settings allow support for stages with both Forward
and Reverse limits.
Note. Typically, the following two parameters are set the same, i.e. both Forward or
both Reverse.
Direction - the direction sense to move when homing, either Forward or Reverse.
Limit Switch - The hardware limit switch associated with the home position, either
Forward HW or Reverse HW.
Zero Offset - the distance offset (in mm or degrees) from the limit switch to the Home
position.
Velocity - the maximum velocity at which the motors move when Homing.
For further information on the home position, see Section D.2.2.
Hardware Limit Switches
Note. The minimum velocity and acceleration/deceleration parameters for a home move
are taken from the existing move velocity profile parameters.
The operation of the limit switches is inherent in the design of the associated stage or
actuator. The following parameters notify the system to the action of the switches
when contact is made. Select Rev Switch or Fwd Switch as required, then select the
relevant operation.
Switch Makes - The switch closes on contact
Switch Breaks - The switch opens on contact
Ignore/Absent - The switch is missing, or should be ignored.
Motor
These parameters are used to set the 'resolution' characteristics of the DC servo
motor connected to the selected channel. The resolution of the motor, combined with
other characteristics (such as lead screw pitch) of the associated actuator,
determines the overall resolution.
Steps Per Rev - The number of encoder counts per revolution of the DC servo motor
(minimum '1', maximum '1000').
