With Ohishi-san, Enzo, Yoshioka-kun.

Today:

• We set the yoke about 2.5 mm lower, so that the distance from the top of the yoke coil former down to the top of the BF baseplate was 3.5 mm (down from 6 mm) and the bottom of the BF baseplate down to the bottom of the yoke support ring was 29.5 mm (up from 27 mm).
• We reset the FR to 35 mm (midrange) and noted the LVDT reading: 267 counts. As hoped it was much closer to zero.
• At this point Enzo increased the gain of the LVDT hoping to use more of the range of the ADC now that the output range was better centered, but overdid it.
• We did a calibration of the LVDT using the FR. The LVDT output ranged from -6400 to +15250 ct and was clearly saturating at the top end.
• Enzo reduced the gain again.
• To save time before doing a proper recalibration we set the keystone height to exactly 66.0 mm (nominal) with the stop screws and tweaked the height of the yoke until we got 730 cts. (A tiny fraction of a turn on the adjustment screws was several hundred counts, so we didn't try for closer to zero.) We checked the LVDT readings at 68 mm (5150 ct) and 64 mm (-3900 ct) to check they were resonably well-centered on zero and not too large.
• Then we did another full calibration (see forthcoming comment by Enzo).
• We set up the optical sensors facing the back of the RM, and set up the driver box with power and connections to the rack. Tomorrow we will adjust the sensors to the proper distance and try to get them working.