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    User name sawatzky

    Log entry time 18:36:54 on April 10, 2007

    Entry number 198497

    This entry is a followup to: 198492

    keyword=New encoder positions not quite right yet -- updated positions in text

    Using the target camera as a guide we have determined that the encoder
    positions for the Carbon, Copper, and Empty target are not correct.
    BeO and Loop 1 look OK.

    Manual adjustment of the target ladder location while watching the
    target monitor gives these values:
    - Carbon: 3550000
    - Copper: 1950000
    - Empty: 400000
    These values are written on the target position paper taped next to the
    target computer monitor.

    It looks like the encoder counts per 'target step' is roughly 1650000.
    This would imply ~65000 counts/mm if the target spacing is 1 inch.
    That is suspiciously close to 2^16 = 65536 counts/mm.
    (Dave had been using 51200 counts/mm in his calculations.)

    The Be0 position looked good, but we will make a visual confirmation
    on that target, and do a run with the Holy Carbon(TM) target once we
    get beam.

    A copy of this log entry has been emailed to: moffit@jlab.org, meekins@jlab.org, hrosinko@jlab.org, gilman@jlab.org