Procedure Calibrate FLARE undulator

Procedure

1. Set the undulator gap to 40mm to allow good access to the measurement points.
2. Measure the gap at the positions indicated by dots on the upper beam. Take care not to put the calipers on the shims.
3. Upstream should now read 140.65 mm (if not, adjust encoder offset)
4. Downstream should now read 140.60 mm

Relevant specification

• Motor: 1200 steps/turn
• Gear ratio: 10 turns/mm
• Motor to gap: 12000 steps/mm
• Encoder reports 51.2 units / mm (non-integer unit increments)

Offsets

Calibration 2018-02-06 @ 40 mm gap

axis	measured distance	actual gap	encoder position	calculated encoder offset
upstream	140.53	39.88	424977.625	422936
downstream	140.75	39.85	1223961.4375	1221921

Calibration 2019-04-29 @ 40 mm gap

axis	measured distance	actual gap	encoder position	calculated encoder offset
upstream	140.65	40.00	424996.9375	422949
downstream	140.70	39.80	1223933.875	1221896

a sensor that encodes position

a device or an algorithm to convert video to a certain digital format