|
Specifies the setpoint for the beam position servo controller.
The beam position sensor outputs two values which are subtracted and normalized.
The control loop adjusts the current in the beam position actuator to drive the
normalized output to a value equal to the bposn parameter.
Changing "bposn" affects the contrast ratio of the head and the stroke cal
noise. Generally should not need changing in the field. If however it is not
possible to get a good beam balance then it is worthwhile trying to change the
bposn by +/- 200 units to see if the noise level improves. The optimal "bposn"
could change from the factory setting if some components in the head shift
slightly.
|