Data Type: Occurs in Image and Force Volume Modes. In Image Mode, Data Type identifies the type of signal displayed in the image window. In Force Volume Mode, Data Type identifies force volume imaging type; the choices depend on SPM. This note discusses force volume imaging based on the deflection signal. Under the Feedback panel, the Data Type of the FV trigger is selectable.
Display Mode: In the Z Scan control panel is set to display in the force plots region the Extend portion of the force curves, the Retract portion, or Both.
Force per line: In the Force Volume panel. Determines the number of force curves collected and stored along each scan line and significantly affects the scan speed. This parameter is, effectively, the XY resolution of the force volume image.
Number of samples: In the Z Scanpanel. Sets the number of points collected in each force curve. This is also the number of slices in the force volume image, that is, the Z resolution of the force volume image. This parameter does not affect the speed of the scan but does affect the file size.
Center plot: In the force curves control panel. Determines where the force plots are graphed relative to the current Setpoint. When Center plot is Off, the center horizontal line of the graph is positioned at the Setpoint value and cantilever deflection is measured from this value. When Center plot is Enabled, the central horizontal line is positioned at the tip noncontact voltage (i.e., voltage when the tip is clear of the surface - the noncontact portion of the curve) from which the deflection is measured.
Samples per line: In the Image Scan control panel. Sets the number of pixels in each scan line of the height image. Total force volume data acquisition time is proportional to Samples per line. This parameter directly affects the XY resolution of the height image only.
Deflection Sensitivity: In the Force Volume control panel. Relates cantilever deflection as measured in photodetector output voltage to topographic height.
Data Type: In the Feedback panel determines the data channel to act as the trigger. Usually, this has the same value as Force Channel/Data Type.
Trig threshold: In the Feedback control panel. Is set to the tip deflection magnitude which causes the piezoelectric actuator to begin retracting if a trigger is in use. Trig threshold limits forces on the sample and tip.
Trigger mode: In the Feedback panel. Determines the type of trigger to be employed: Relative, or Absolute. A Relative trigger measures the trigger threshold relative to the noncontact deflection voltage value, so compensates for drift. An Absolute trigger measures the trigger threshold with respect to Setpoint.
Data Center: Under the force volume images. Adds/subtracts a constant value to/from the data signal (deflection in the case of contact mode force volume imaging). This is used to center the force volume data within the FV scale bar.
Data Scale: Under the force volume images. Sets the range of values displayed by the force volume image in RealTime.
Z direction: In the Force Volume control panel. Determines which portion of the Real-time force curve cycle, Extend or Retract, is shown in the force volume image region. Z direction is also found in the Offline Parameters list of a captured force volume.
Z display: Under the Deflection Error slice image. Determines which slice of the force volume is displayed in the force volume image region. Z display is also found in the Offline Parameters list of a captured force volume.
Data Scale: Under the Height image. Sets the range of cantilever deflection values plotted in the force curves region.
Ramp Rate: In the Z Scan panel sets the rate at which the AFM collects a force curve, both extending and retracting portions. Ramp Rate and Samples per line determine the time to collect a force volume data set.
Ramp size: In the Z Scan panel. Sets the excursion size for the probe during the extend and retract portions of a force curve. When the cantilever deflects an amount equal to Trig threshold, the piezoelectric actuator retracts one Ramp size before beginning the next curve.
Z scan start: In the Z Scan panel. Sets the starting position of the piezoelectric actuator for the first force curve only.