Noise of act 484. Investigation

the visual inspections showed one wire of the coil touching the "orpello" inside the refplate hole. Possible source of interference between coil current/voltage and capsens signal. The wire has been bent to avoid touching. The shell has been set and noise tested. The gain are low because the miniskert is dismounted.

  • test noise:
    • 20100916_170141: The act#484 does no longer have high noise
    • 20100916_170235: same as previous
    • the result of the test has to be confirmed when the miniskirt will be mounted back allowing setting the shell with high gains

Actuator(?) touching horizon pointing

slew the unit toward horizon:
  • 90 to 0deg el. slew: from 20100916_171605 to 20100916_171705. Peak gap goes from 39 to 54 um. Repeate measurement with 1/8 of reference wave to reduce the capsens saturation level
  • 171911: find touch
  • 172028: find touch
  • 90 to 0deg el. slew 1/8 reference wave: from 20100916_174026 to 20100916_174114.
    • actuators that start increasing the gap with max slope are 147 an 38. The two actuators have a disabled actuators in between (act #39). Require new measurement including the reading of act 39
  • 90 to 0deg el. slew 1/8 reference wave, data in $ADOPT_MEAS/adsec_calib/slew4touch.sav. using read_dsp_ch for reading also actuator #39
    • 39,38,147 grow gap with the same slope
    • try to move the actuator up:
      • 39: no change, but it seems to be already at the end of its travel up
      • 147: no change, but it seems to be already at the end of its travel up
      • 38: no change, it sensitively moved up (some tenths of mm). It needs to be relocated.
    • pushing acts 150 and XXX with 10-grams order force the gap goes down to 38um. Pressing neighbor actuators produce very less change in the gap: IT IS NOT A HARD STOP
    • test to set the shell at 20deg elevation to see if the feature reduces functionality:
      • problem in setting the shell. The coils at the beginning are seen not enabled and the procedure exits. Patched increasing the number of iterations to check the status of coils from 3 to 21 ( line 364). Patch worked well detecting three failures in the following cases 20100916_230403 and 20100916_230830, in the old case (just 3 attempts) the procedure would fail
      • set shell at 0deg el.; swing at 20deg el.; rest the shell: WITH THIS SEQUENCE OF OPERATIONS THE GAP IN REST POSITION IS NOT LARGER THEN 39um. from previous condition setting the shell at 20deg el. is OK
      • at 20deg, rest the shell, again max gap 39um. Setting the shell is OK
      • 233800 slew 90-20deg with shell in rest position. Max gap 39um NO LONGER seeing 50um gap
      • repeated several times: no longer seen 50um gap

Opticote removal

  • removed in a single spiral from the center to the external edge
  • magic tape to remove residuals from the shell edge

Installation of the central dust cover

  • shim used: 0.7mm, min gap about 400um
  • the neoprene edge is quite irregular giving locations with gap more than 500um
  • next time change the procedure: find the shim that makes the neoprene touching and then add shim to set the desired gap. Rotate the cup to find the best uniformity of the gap.

Cleaning and installing the miniskirt

  • started at 19:30 local time
  • checked astaic levers and accelerometers

ERRORS to mention

  • when the reference wave is 1/8, the fastdiag gives an alarm

  • during setting:
IDLCTRL00          |ALW|       925|2010-09-16 21:57:41.744938|             MAIN > mean req pos   : 4.00002e-05
IDLCTRL00          |ALW|       926|2010-09-16 21:57:41.745045|             MAIN > % Detected at MOMENT            137 /usr/local/itt/idl71/lib/
IDLCTRL00          |ALW|       926|2010-09-16 21:57:41.745045|             MAIN >  . % Program caused arithmetic error: Floating divide by 0
IDLCTRL00          |ALW|       926|2010-09-16 21:57:41.745045|             MAIN >  . % Program caused arithmetic error: Floating underflow
IDLCTRL00          |ALW|       926|2010-09-16 21:57:41.745045|             MAIN >  . % Detected at MOMENT            143 /usr/local/itt/idl71/lib/

  • ERRORE with ADAM. Starting from scratch the system as usual:
    • fsm_power_on(): OK
    • fsm_load_program(/AUTO): OK

-- ArmandoRiccardi - 16 Sep 2010
Topic revision: r4 - 17 Sep 2010, ArmandoRiccardi
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