User`s guide

Closed-Loop Scanners 9
Agilent 5500 SPM User’s Guide 154
Positional drift that may be present in an open-loop system is
continuously corrected with the closed-loop sensor.
In the Spectroscopy window you can select the Sensor as Topo check
box to use the Z sensor signal instead of the Deflection signal for
generating topography images.
Checking Z Position in the Spectroscopy window will precisely
maintain the cantilever at a defined height above the sample for
specialized experiments, such as measuring how long molecules stretch
and relax.
X/Y/Z Closed-Loop Scanner
The X/Y/Z closed-loop scanner includes the functionality of the Z-Axis
scanner described above, with additional encoders on the X and Y axes.
These sensors allow for very linear scans and also make it easy to move
to precise locations on the sample.
Calibration
Agilent recommends calibrating the Gains, Offset and Sensitivity prior
to each use of the closed-loop scanner. Begin by calibrating the scanner
following the open-loop instructions in the Chapter 8, “Scanner
Maintenance and Calibration.”
For a Z-axis scanner, skip to “Z Sensor Calibration" on page 158 below.
X and Y Sensor Calibration
Initial calibration of the X and Y sensors consists of matching the ±10 V
output range of the sensors with the actual piezo travel, which varies
from scanner to scanner. No sample is required for this procedure.
1 Load a cantilever and set up the 5500 SPM for Contact Mode
imaging.
2 Verify that the correct scanner calibration file is selected in the
Scanner menu.
3 Choose Scanner >Edit to open the Scanner Setup window
(Figure 106).