User name Sulkosky
Log entry time 18:34:23 on August28,2003
Entry number 114096
This entry is a followup to: 114065
keyword=Target Lifting Motor
During the Day shift, there was a problem moving the target ladder. When the target was moved to the Multi-foil position the GUI did not respond. The TO hit the Home Routine trying to fix the problem, but apparently this caused the vertical axis on the lifting motor to be redefined. When they moved the target to the Multi-foil position, the position was off by -49.3 revolutions or 20.7 mm. From my calculation this position was mid-way between the Polarized 3He position and the Long 12C Foil position. It was 1.75 cm from the center of the polarized cell and 1.07 cm from the Long 12C foil position. I am surprised that MCC was able to send beam in this position, since neither FSD switch should have cleared. When the target was moved to the Long 12C position, the FSD did not clear. This position was 7.5 mm below the 3He cell. The FSD switches have a few mm's of tolerance, but not a cm. So the above situation should be looked at during the shut down.
To fix the target position problem, I went into the hall and moved the lifting motor to the upper limit switch by using the keypad. This position is know very well, so I then reset the position on the GUI to correspond to correct upper limit switch position. After I reset the axis for the encoder positions, I checked with MCC to make sure that the FSD switch cleared for the reference cell and Multi-foil position.