Figure 11.4B False Engagement (G Scanner) - Veeco 004-210-000 Instruction Manual

Tip
Deflection
0.48 V/div
Setpoint
Motor Control
Motor Control > Tip Up and Tip Down buttons provide coarse adjustment of Z center voltage.
With these buttons the SPM head moves vertically. The feedback loop causes the Z piezo to adjust
to compensate for the head movement. If you use Tip Up, the Z piezo extends. If you use Tip
Down, the Z piezo retracts.
Note:
Adjust Photodiode
In an analogous manner, you can use the photodiode positioner as a coarse adjustment for Setpoint
voltage. Changing the laser beam position on the photodiode by rotating the photodiode adjustment
knobs shifts the force curve on the graph. Rotating the top photodiode adjustment knob counter-
clockwise shifts the curve up, just as decreasing the Setpoint parameter shifts the curve up.
Conversely, rotating the top photodiode adjustment knob clockwise moves the curve down.
Rev. B

Figure 11.4b False Engagement (G Scanner)

Retracting
Extending
Z Position - 9.27 V/div
The Step Motor function is generally used only when the scanning range of the
Z piezo is exceeded or when it is necessary to position a force measurement in
the center of the scanner range. Because the Z-axis leadscrew has some
backlash, it may be necessary to rotate the leadscrew several turns by clicking
on the Tip Up or Tip Down buttons before obtaining movement.
MultiMode SPM Instruction Manual
Force Calibration (Contact Mode AFM)
Possible False Engage Points
Force Imaging
193