LM1 calibration DX

Measuring the LM1 limit switch position as well as the optical and mechanical zero position.

Lower limit

AbsEnc IncEnc SW setting
1913 -5145 2000
595 -2982 600
606 -4850 700

Mechanical Zero (distance was measured on the outer part of the mirror)
AbsEnc IncEnc Distance mirror [mm]
20602 2154 26.7
21287 5111 26.7
11046 -765 26.7
Optical Zero

AbsEnc IncEnc Distance mirror [mm]
16253 455 26.45
17712 3715 26.3
23316 4028 27.8

Upper limit
AbsEnc IncEnc SW setting
47230 12555 47200
44490 14175 44400
46186 12961 46100
IncEnc values will change after setting the Zero position to the mechanical in SW.

Conversion factor was measured to 5000.

Interactuator range was set to 7600 (double as before, as movement is about half the way as before)

Open points:
  • in case the motor moved for any reason over the limit the tripod software can not recover
  • would be useful to have button to set the nominal AbsEnc position (mechZero and optZero)
  • show the absolute phi and theta


We performed some preliminary checks on the TipTiltSystemDx:

  1. We measured the position of the biggest aperture in the ApertureWheel: we made use of the FLAO IS and defocused the Z stage to have >5" spot on the QuadCell. Then we started to rotate the aperture wheel and recorded the fluxes of the 4 APDs.
  1. we saw that the dichroic in the FW1 was creating 2 spots on the QC ruining the linearity measurements and also the flat acquisition
  2. we evaluated the geometry of the 4 APDs:
  3. we tryed to acquire a first flat to measure relative efficiency of the 4 channels.
  4. we tryed to identify the direction of the board stages axes wrt the QC itself.

Topic revision: r2 - 21 Feb 2015, MarcoBonaglia
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