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T-Cube Position Aligner
Output: Min and Max Limits (V)
- These parameters are applicable only when operating
in closed loop mode. The XOut and YOut values are the low voltage signals sent to the
LV OUT/XDIFF and LV OUT/YDIFF connectors, which are then used by the piezo T-
cubes to drive the piezo mirror in order to keep the beam central in the detector. (See
the next topic for a typical application.
Under normal operating conditions, these values are between -10 V and +10 V
however, some applications may require the limits to be less than this. The Position
Demand Output Limits can be used to set the limits for the XOut and YOut values,
between -10V and +10V.
GUI Grid Display
- As previously described, the difference signals indicate the beam
position on the detector in the X and Y axes. The SUM signal can be used to 'normalize'
the difference signals in relation to beam power. For example, consider the situation,
where the beam is positioned in the upper right hand quadrant of the detector. In this case,
the XDiff and YDiff signals may be '8' and '2' respectively, giving a sum value of '10'.
If the beam power were to be reduced by half, due perhaps to the fitting of a filter, the XDiff
and YDiff values would then be '4' and '1' respectively. Viewed in isolation, these values
indicate that the spot has moved nearer to the center. It is only when the values are
'normalized' and considered together with the sum value, now '5', that the true picture
becomes apparent.
Click the
‘Normalise X, Y Difference Signals to Sum Signal
’ checkbox if normalization
is required
Position Demands In Open Loop Mode
- This parameter sets the value of the drive signal
from the XDiff and YDiff connectors when the unit is switched to from closed loop to open
loop mode.
If set to Held Outputs, the outputs are fixed at the values present when the unit is
switched to open loop.
If set to Zero Outputs, the output is set to zero (0V).
Persist Settings to Hardware
- Many of the parameters that can be set for the position
aligner can be stored (persisted) within the unit itself, such that when the unit is next
powered up these settings are applied automatically. This is particularly important when the
driver is being used manually in the absence of a PC and USB link. The following parameter
settings can be altered and then persisted in the driver for use in absence of a PC:
Control Loop PID Settings
HW Disp Intensity
Position Demand Output Min and Max Limits
LV Signal Routing
Position Demands in Open Loop Mode
Position Demand Feedback Sense
To save the settings to hardware, check the 'Persist Settings to Hardware' checkbox
before clicking the 'OK button.
