aLIGO LHO Logbook

H1 SEI (ISC, SEI)

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sheila.dwyer@LIGO.ORG - posted 09:53, Friday 24 January 2014 - last comment - 10:45, Friday 24 January 2014(9536)

Instructions for recovering from a HEPI trip on ITM or ETMX

Hugh gave me instructions for recovering from a HEPI and ISI trip on ETMx, which should work for the ITM:

1) turn off any large inputs from lsc to hepi, set a large ramp time for reengaging it later.

2) untrip watch dogs

3)isolate level 1

4) check RX +Ry (or all) current set points (in the bias screen) to see if they are the same as the target setpoints, if not set them to be the same. (this should only be a problem for the ETM)

ISI:

1)in watchdog screen set T240 limit to something large (only needed for ETM)

2) reset watch dogs if they are tripped

3) commands undamp (may not be necessary, especially if drives are small)

4) for ETM, make sure stage1 blends are all 750mHz

5) Isolate level 1

6) after that is done make sure that St 1 blend_x and blend_Y are T100mHz_N0.44 for the ETM. For the ITM make sure that Sebastians Notch_narrow (for the 0.5Hz noise) is engaged.

I think that is all!

Comments related to this report

brian.lantz@LIGO.ORG - 10:45, Friday 24 January 2014 (9540)

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7) Once the T240s have settled down  (max of 5 min or so, but hopefully less if there is not a lot of tilt imposed), put the T240 Watchdog level back to its nominal operating point by pressing the 'reset' button on threshold level of the T240 in Watchdog screen. In any case, this should not be a problem, because the T240 blends will not work until the T240s have stopped saturating.