aLIGO LHO Logbook

H1 SUS

betsy.weaver@LIGO.ORG - posted 15:53, Thursday 12 March 2015 - last comment - 13:40, Friday 13 March 2015(17229)

ETMy SDF cleanup leads to ETMy ESD cleanup

Due to all of the latest commissioning of ETMY, the SDF had accumulated 40+ differences. With Jeff's help we remedied numerous line items via making the ETMy ESD banks look like the ETMx ones. This cleared out Kiwamu's settings leftover from earlier measurements. I've also moved the ESD calibration filters from the 4 ETMY L3 ESD OUTPUT banks to the L3 LOCKING BIAS bank to bring it in line with the ETMx settings. I've edited the burt ETMy safe.snap to capture some of the other commissioning work. THere are now only 20 SDF diffs which I will continue to track down.

Comments related to this report

betsy.weaver@LIGO.ORG - 15:54, Thursday 12 March 2015 (17230)

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Screen snapshots before ETMy cleanup:

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betsy.weaver@LIGO.ORG - 15:55, Thursday 12 March 2015 (17231)

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ETMy screen snapshots now:

Images attached to this comment

jeffrey.kissel@LIGO.ORG - 18:11, Thursday 12 March 2015 (17238)

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To specify what Betsy means when she says "This cleared out Kiwamu's settings leftover from earlier measurements," we cleared out the EFF_CHARGE values in ESD linearization block, and changed the FORCE COEFFICIENT to match ETMX, at -124518.4 (see LHO aLOG 16798 and 16843). 

This force coefficient is -124518.4 [ct] (i.e. raw DAC counts, NOT LOCK drive counts), representative of the bias voltage of 9.5 [V] (referenced to [V] output from the DAC, NOT on the ESD), or an bias voltage on the ESD of 380 [V]. As the commissioning vanguard prefers DAC voltage, we've entered 9.5 "[V]" into the LOCK_INBIAS, and calibrated FM1 accordingly. This is exactly how EX is configured, as Betsy says.

kiwamu.izumi@LIGO.ORG - 13:40, Friday 13 March 2015 (17252)

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Betsy, Jeff,

Thanks for cleaning up the mess and I am sorry that I did not alog the details. Regarding this configuration, I actually liked the ETMY configuration than ETMX because (1) the effective charge can be calibrated in Volts at the electrodes and (2) the bias voltage can be specified on the medm screen as the actual voltage at the electrode e.g. +380 V. We should decide which calibration convention we want to use. I will talk to you guys about this once I come back.