ifocus Command


This page is part of the ING manual WHT-INGRID-2: INGRID IMPB Software Operations Manual


 
Usage: ifocus  focus_pos | "datum"
Category: Mechanism Command
Description: This command moves INGRID's focus drive mechanism.

The focus mechanism is used to optimise the sharpness of INGRID's images by moving the ingrid detector either backwards or forwards within the instrument's light path.

The optimal focus position may be determined by taking a sequence of exposures at different focal positions and analysing the images for sharpness using INGRID's data reduction facility. The focusrun script has been provided to facilitate this.

Periodically (and certainly after power cycling the EPICS Controller) it will become necessary to datum the mechanism.  To do so the "datum" argument may be specified. After datuming, the focus mechanism will be left at the datum position. It should be moved back to some nominal focus position.
 
Arguments: The command takes a single argument which may either of:
  • focus_pos - an integer between -1000 and +1000 specifying the required focus position (in microns).
  • "datum" - a string literal which indicates that the pupil imager is to be datumed. 
Examples: ifocus 700 - set focus position to +700 microns.
ifocus datum - datum the focus mechanism.