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Reports until 17:42, Friday 25 July 2014
H1 SEI (INS)
hugh.radkins@LIGO.ORG - posted 17:42, Friday 25 July 2014 (13008)
WBSC1 ITMY HEPI Position Loops on with New ACB Hang

Took a snap shot of the ITMY HEPI position at various times: IAS align good (Tuesday Rz & X), SUS completes payload hanging on ISI (Wednesday Rx & Ry), and finally today when the ACB was hung on.  I'll hold the positions to these times.  With the ACB install the Z has shifted down seemingly a lot but actually only 160000nm.  I've closed the loop and used this target and the loop is fine but it isn't our practice to 'target' the Z DoF.  Rx & Ry I do want to hold although again the amount of shift isn't huge: -78000 & 20000nrads.  But this is tilting HEPI and changing the hang of the ISI stages although likely not to 1st order; our level Spec on ISI is 100urads.  Y shift from alignment time to now in only 4um.

Target values: X/RX/RY/RZ == 300000/15000/56000/-16200

Previously as reported, the Ry loop has not been stable; interestingly it seems to be happy now.  Of course the ISI & SUS both were locked for the ACB install...

Meanwhile, I have Guardian controlling HEPI for all DoFs and holding position on X, Rz, Rx & Ry.  We'll try to off load the X, Rx & Ry to the HEPI Springs at a later time. Yeehah!

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