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 Wed Mar 13 03:12:47 2013, Manasa, Jenne, Update, Locking, TWO arms TWO colors
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 Wed Mar 13 08:34:33 2013, yuta, Update, Locking, TWO arms TWO colors
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Wed Mar 13 16:29:25 2013, Manasa, Update, Locking, TWO arms TWO colors
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Wed Mar 13 10:26:58 2013, Manasa, Update, Locking, We're still good!!
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Mon Mar 25 15:01:33 2013, Manasa, Update, Locking, TT1 drift
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Mon Mar 25 15:24:41 2013, rana, Update, Locking, TT1 drift
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Message ID: 8336
Entry time: Mon Mar 25 15:01:33 2013
In reply to: 8282
Reply to this: 8337
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| Author: |
Manasa |
| Type: |
Update |
| Category: |
Locking |
| Subject: |
TT1 drift |
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| Quote: |
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2. TT1 drifting in pitch (Bistable)
During the arm alignment routine for spot centering, we observed that TRY dropped (from TRY = 0.9 until the arm lost lock) every 40minutes or so. The arm was relocked by moving TT1 in pitch. The (locking - unlocking due to drift - relocking) cycle was monitored and we observed that it was bistable i.e. if TT1 was moved up in pitch (0.2 on the slider) to relock for the first time ; the next time it lost lock, TT1 had to be moved down by nearly the same distance to relock the arm.
Moving TT2 or the testmasses did not help with relocking the arms; so TT1 seems to be the one causing all th trouble atleast for today.
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Update
TT1 was moved in pitch to restore flashing in the arms on Wednesday (Mar 20) so that it doesn't drift too far off making it difficult to lock again. Since then, the arms have been flashing without any drifting and TTs have remained untouched. The hysteresis has disappeared. |