Abbreviated Instructions for the MultiMode AFM
34
Scanning Probe Microscope Training Notebook
Rev. F
15.7 Adjust Photodiode Signal
Note where the laser reflection enters the photodiode cavity. If necessary, adjust the mirror (lever
on back of optical head) to center the laser reflection into the photodiode cavity. Leave the mirror at
an angle such that the
SUM
signal (circular meter in bottom LCD) is maximized.
•
Tapping: Adjust the
Vertical Difference
value (bottom LCD) to zero using the screw on
the top left side of the optical head.
•
Contact: Set the
Contact AFM Output Signal
value (Vertical Difference, top LCD) to
-2.0V using the screw on the top left side of the optical head. Adjust
Horizontal
Difference
value (bottom LCD) to zero using the screw on the back, left side of the
optical head.
15.8 Cantilever Tune (TappingMode Only)
Select
View
>
Cantilever Tune
(or select the
Cantilever Tune
icon). For Auto Tune Controls,
make sure
Start Frequency
is at 100 kHz and
End Frequency
is at 500 kHz.
Target Amplitude
should be 2-3 volts. Click on
Auto Tune
. A “
Tuning...
” sign should appear and then disappear
once Auto Tune is done. When finished, quit the Cantilever Tune menu.
15.9 Set Initial Scan Parameters
In
Scan Controls
panel, set the initial
Scan Size
to 1 µm,
X
and
Y Offsets
to 0, and
Scan Angle
to
0.
•
Tapping: In the
Feedback Controls
panel, set
Integral Gain
to 0.4,
Proportional
Gain
to 0.6, and Scan Rate to 2 Hz.
•
Contact: In the
Feedback Controls
panel, set the
Setpoint
is to 0 volts, the
Integral Gain
to 2.0, the
Proportional Gain
to 3.0, and the
Scan Rate
to 2 Hz.
15.10 Engage
Select
Motor
>
Engage
(or select the
Engage
icon).