aLIGO LHO Logbook

H1 PSL (PSL)

peter.king@LIGO.ORG - posted 08:05, Wednesday 06 March 2019 - last comment - 15:28, Wednesday 06 March 2019(47328)

RFPD DC readback

The adapter box that interfaces between the DB9 of the RF photodiode and the DB15 of the TTFSS field box was
opened.  On the DB15 side, there is 1M in series with pins 5 and 13.  These reduce the nominal gain of the
RFPD DC monitor output from -1 to -0.01, which would explain the low number of counts observed.

    Otherwise the number of counts for ADC channel 6 is consistent for the input applied voltage.



  Richard / Peter

Comments related to this report

peter.king@LIGO.ORG - 09:06, Wednesday 06 March 2019 (47330)

Link

Fil and Richard fixed this, this morning.  The two 1M resistors were removed.

    The gain factor of -0.100 was changed to -0.0006103515 (ie the counts to volts conversion) to better reflect things.

betsy.weaver@LIGO.ORG - 13:06, Wednesday 06 March 2019 (47339)

Link

This is a continuation of determining this was broken at:

https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=47140

jeffrey.kissel@LIGO.ORG - 15:28, Wednesday 06 March 2019 (47347)

Link

This adjustment has been tracked in FRS Ticket 12386.

Jason / Peter are waiting for confirmation of success before closure.