Shane AO  

Problem: TT CAM Motor Failure

Manifestations:

TT Cam X (vertcal motion in standard ShaneAO park postion):

In Shane AO motor control GUI:

• Function fails to re-calibrate (perhaps following a re-start of dispatcher saomot2).
• TT CAM X function flagged with either a red check mark and/or yellow warning triangle.
• Motor fails to move, ceases moving or fails to acheive commanded position.

TT Cam Y (transverse motion in standard ShaneAO park position):

In Shane AO motor control GUI:

• Motor fails to move, ceases moving or fails to acheive commanded position.
• TT CAM Y function may not be flagged with either a red check mark and/or yellow warning triangle.
• Motor calibrates successfully, but fails to acheive commanded position via GUI, or via command line, e.g.

  user@shred > modify -s saomot ttcamyraw=1000

• No amount of changing mode between Halt, Pos, Pos ON, etc. changes the behaviour, even after calibrating the function.

Work-around (W. Deich, 2018-11-06):

• To check what the Galil thinks, inspect Galil variable _BX<axis> (i.e. _BXF for TT Cam X; _BXE for TT Cam Y). The values are: 1.0000 for an uninitialized brushless motor; 3.0000 for an initialized brushless motor. For (TT Cam X) example:

   
     user@shred.ucolick.org > saomot.io ctrl1aux='MG_BXF' 
     [...] 
     3.0000\n: 
     

• To force the Galil to consider the value uninitialized, use the BX command with the illegal value 0. For (TT Cam X) example:

   
     user@shred.ucolick.org > saomot.io ctrl1aux='BXF=0' 
     [...] 
     ? 
     

  The ? response means the Galil rejected the command. However, checking _BXF should reveal it is now 1.0000. For (TT Cam X) example:

   
     user@shred.ucolick.org > saomot.io ctrl1aux='MG_BXF' 
     [...] 
     1.0000\n: 
     

• Now, it should be possible to re-calibrate the stage.
• A final check should respond that the stage is now initialized (i.e. set to a value of 3.0000). For (TT Cam X) example:

   
     user@shred.ucolick.org > saomot.io ctrl1aux='MG_BXF' 
     [...] 
     3.0000\n: 
     

Solution/Recovery:

TT Cam X (vertcal motion in standard ShaneAO park postion):

• Turn the TT CAM X motor on:

  user@shred > modify -s saomot ctrl1aux='MG_VXF'

• Release the TT CAM X brake:

  user@shred > modify -s saomot ctrl1aux='BZF=-4'

• In Shane AO motor control GUI, via the TT CAM X detail panel, select Re-calibrate.
• Refer to Motor Control GUI Start-up Procedure for current nominal on-axis positions.
• If unsuccessful, refer to recovery procedures for General Motor Failure.

TT Cam Y (vertcal motion in standard ShaneAO park postion):

user@shred > ao restart saomot1

Verify TT CAM X status.

It may be necessary to re-calibrate TT CAM X in order to clear off-on error messages:

• To home TT CAM X, release the TT CAM X brake:

  modify -s saomot ctrl1aux='BZF=-4'

• In Shane AO motor control GUI, via the TT CAM X detail view panel, select Re-calibrate.

Refer to Motor Control GUI Start-up Procedure for current nominal on-axis positions.

If unsuccessful, refer to recovery procedures for General Motor Failure.

Intervention:

• WARNING: Be extremely cautious if intervening on TT Cam stage. Beware of fast motions and small clearances.
• Visit ShaneAO. Identify Tip-Tilt camera stage (e.g. by observing during a calibration attempt).
• Gently provide some upward pressure (support underside of moving stage) on Tip-Tilt camera stage during a further calibration attempt.
• Re-attempt solution/recovery above.
• Consider lubricating motor stage(s) and/or associated limit switches.

Cause:

• Galil motor controller believes it knows the brushless motor's phase, but it is incorrect, causing motions to fail badly: TT Cam X tends to free-fall; TT Cam Y tends to move at high speed into a limit.
• Brushless motors have insufficient capability to move significant weight of moving (TT Cam X) stage against gravity. An assistive spring was added in October 2018.
• Possible binding of motor stage(s) and/or associated limit switches.

Effects:

• When shutting down the system, ensure the 24V brake power supply is turned off before the Galils, since the break is on when there is no power to it. This prevents TT Cam X stage from falling under gravity (thus blocking access for subsequent dewar fills) when power is removed (Issue 10624).

Associated Issues:

• Issue 10607 (TT Cam X & TT Cam Y).
• Issue 10620 (TT Cam X).
• Issue 10624 (TT Cam X).
• Issue 10625 (TT Cam Y).

Change Log:

2018-11-19: Updated. Amalgamated TTCamX and TTCamY troubles into a single common problem page. Added new workaround from W. Deich.

2017-10-03: Updated. Added effect of falling TTCAMX stage.

2017-08-05: Updated (binding/lubrication of limit switches).

2016-11-11: Updated (shred replaces shard).

2015-07-01: Updated.

2014-05-09: First version.