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Reports until 14:41, Wednesday 06 August 2014
H1 SEI
hugh.radkins@LIGO.ORG - posted 14:41, Wednesday 06 August 2014 (13241)
WHAM3 Cart Bias Reset--makes sense but it doesn't make sense--Restoring all Target DOFs?

The ISI was tripping and I saw it was because the deltas between free position and the targets were too large.  I didn't realize we were restoring all DOFs, I thought we only restored the RZ (Yaw) except for a few other special case locations.  This tripping was happening during the RX & RY target restores and maybe this makes sense.  The payload/balance changed on HAM3 (as on many others) and the balance was done well within spec.  See the first attachment for the CPS Local shifts during my balance on July24. This looks pretty bad even though our spec is +-1600 counts.  This is a 2 day plot though and there may be some detail in the time I actually balanced, like, since the payload changed here so might some distortion on the table and a new CPS zero/lock comes about.  Regardless, it is still within spec even though I feel this could have been balanced better.  See the second plot though for the real problem.  Since the free hanging position moved, of course so did the cartesian position.  Since the current ISI control scheme is restoring the target bias of all DoFs, the controller has a lot further to drive to the target and hence the trip.  Tried several times with Guardian and ISI scripts and same thing.  I reset the Targets to the current free hanging position and all is well. The third plot is the shift in the target position for the record if someone needs to steer back.

 

WHAM3 is currently under managed Guardian control at ISOLATED.

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