BEST
User’s Manual
BEST Local GUI
37
Figure 26
: Beamline Configuration window: bias voltage module settings.
4.4
Region of Convergence and Region of
Interest
Before enabling the PID controller, the user should set precisely the region of
convergence and the region of interest areas. By clicking on
Settings->ROC/ROI
a
new window shows up which enables user to set the desired values (see
Figure 27
).
Figure 27
: ROC/ROI Settings window
The Region of Convergence (ROC) is the maximum area where the PID controller
stabilizes the beam to a certain setpoint. If for any reason the beam position goes
outside of this area, the controller stops and shows the error: Beam out of ROC.
The Region of Interest (ROI) defines the area where the target beam position can be
set by the user, either by pointing and clicking (
Figure 18
) on the XY graph or by
entering the desired values. The ROI can be, at most, as large as the ROC, whilst
typically the ROC includes a larger area than the ROI in the X-Y space.