5.4 The quMotor Module
Position: This eld displays the actual position of the linear actuator. You can also
manipulate the value. Please understand that this simply shifts the scale. It is
usually best to manuall set the position of the actuator to a dened position (perhaps
a marking) and then set the position eld to zero.
Target: This eld indicates the target position of a measurement scan. Once started, the
actuator will move in steps of Stepsize towards this target position.
Stepsize: The measurement scan will be done in steps of the size indicated here. This
parameter can only be manipulated in multiples of the stepper motor stepsize which
is
1
/
3200
mm. The display changes accordingly when the stepsize eld has focus.
Integration Time: This sets the integration time per measurement point.
The measurement scan is started with the Start button. Once the scan is completed,
the state of the arrow button determines how the target position is updated:
The position where the last scan started from becomes the new target position.
Useful to scan across the HOM-dip back and forth.
The target is incremented by the length of the last scan. Useful to search for the
HOM-dip by scanning 1 mm, then the next and so on.
The data acquired can be stored on an attached ash drive with the USB (
) button.
5.4 The quMotor Module
The quMotor module is controlled with this tab which is only displayed when the motor
driver option is installed: the Motor Positions tab is shown in gure
5.4.1 Motor Positions
In the Motor Positions tab you can change the absolute position of the motors in the
range from -400
◦
to 400
◦
. This is done by selecting the position eld and adjusting the
value using the rotary encoder.
The angular positions are relative to the magnetic hardware references of the motors
. In
case these angles are not valid anymore i.e. after the motors had been blocked or moved
by hand valid positions can be obtained using the Go to Zero button.
To account for the angle between the magnetic reference of the motor and the installed
optical element, an oset value can be stored. For this purpose a button make Zero
is displayed in expert mode. When pressed, the motor measures the angle between its
current position and the magnetic reference and stores this value as a the new oset. In
this way, even a manually set position can be stored as the new zero position. A second
2
The hardware reference is realized with a hall sensor and a small magnet on the circumference of the
large wheel.
quCR Manual Version 3.2 Page 18
