EdgeGrooveHyrda.spt is used to determine the best drum position for the plate edge detect sequence.
This script requires a plate to be loaded and assumes the host controller is an MCE and the drum is similar to a 3244-type drum.
The problem in the 3244-type application is that the edge detect groove is so close to the leading edge clamp that there is no way to get a leading side signal from which to derive the best edge detect drum position. By doing the second pass over plate we can observe where the leading edge limit is.
The first pass is done at a carriage position where there must be no plate. The focus lens is contracted, for earliest exit of the focus beam from the edge detect groove. The second pass is done at a carriage position where there must be a plate. The focus lens is extented for the latest clearing of the clamps. The scripts asks for the carriage positions. Note that you cannot do an edge detect to know, because it doesn't work yet.
To create the worst case conditions, turn the focus laser transmitter on at full power and the focus receiver at full gain for the edge detect groove pass. Thus the focus SUM signal will rise to saturation as fast as possible. The on-plate pass is done at nominal settings for the active media.
The resulting graphs represent the limit possible for a given head install on a given machine. Select the operating drum position for edge detect in the middle of the O.K. area.
IMPORTANT NOTE: The off-plate carriage position must be selected so that the focus beam ends up NOT over one of the wide grooves for the clamp bands, since for Hydra the worst case seems to be not over the bands (this is different than for EdgeGroove3244.spt).
In the example graphs below, one was done properly, and one was done with the focus beam over a clamp band groove.
When to run this script: Anytime a TH2 head is installed, or its mounting is adjusted, on a Hydra-type engine with an MCE host. Also, use it if you ever have troubles with image shifting in the subscan direction and towards the home position.
Instructions:
NEWSENG>> NEWSENG>> set edge PRM edge parameters: Group Parameter Active Default Units --------------------------------------------------------------------------- edge DrumPos 3.000 0.000 degrees *** Command Complete NEWSENG>> NEWSENG>> set edge drumpos 3.2 'edge DrumPos' changed from 3.000 to 3.200 degrees *** Command Complete
