© ICSPI Corp. 2007-2021
nGauge AFM User Manual 2.0
29
Integral
The integral coefficient of the PI controller.
Increasing this value increases the
response time of the controller but
increasing it too much can cause
instability in the Z actuator.
Can be safely changed during scanning.
0
– 10,000
Setpoint
The tip oscillation amplitude that the
controller will try to maintain. A lower
setpoint is analogous to applying a larger
force between the tip and sample.
50% of
the
maximum
amplitude
on the
Sweep
page
Enable/Disable
Turns on or off the PI controller that
maintains a constant tip oscillation
amplitude equal to the setpoint by
controlling the Z actuator (Fine Z).
Warning:
Disabling the controller while
engaged may damaged the tip.
N/A
N/A
5.7.
Scanning Recommendations
5.7.1.
Changing the scan size
Changing the scan size considerably (for example from 20 micron to 1 micron) can cause the tip
height to move out of the center of its range. For this reason, it is recommended to disengage
and re-approach before changing the scan size considerably.
5.7.2.
Fine Z and Vertical Scan Range
The vertical scan range is important: if the tip leaves the scan range, there is a possibility that
the tip will crash into the sample (at the bottom of the range) or will lose contact with the sample
(at the top of the range).
The height of the tip is represented by the Fine Z on the Approach page. The range is from 0 to
3.3 V.
When the Approach button is clicked, Fine Z gets set to just below the middle of its range
(approximately 1.5 V):
