filiberto.clara@LIGO.ORG - posted 16:18, Tuesday 09 February 2016 - last comment - 05:08, Wednesday 10 February 2016(25468)
ETM ESD Electronics
Modified the ETM LVLN ESD Drivers (ECR E1500341): 1. Changed C32 in the monitoring amplifier from 1uF to 10nF to put the pole frequency at 4.244kHz 2. Changed C36 in the summing node from 1uF to 0.047uF to increase the dynamic range EY Unit SN S1500066 EX Unit SN S1500073 Replaced the ESD AI chassis in SUS-C1 (EX/EY). New AI Chassis contains the PI Band Pass Filter D1500177. Cable H1:SUS_ESD-05 had to be re-terminated with a DB9 male connector to accommodate new AI front panel interface. EY Old D1100815 Unit SN S1103824 EY New D1500177 Unit SN S1500300 EX Old D1100815 Unit SN S1103820 EX New D1500177 Unit SN S1500299
Evan, Keita
The above means that the actuation function changed due to C36 change.
That capacitor, together with R50 and R51, used to provide
zpk([152], [3250]), but now this should be zpk([3225], [67725]).Correction: used to provide zpk([3250], [152]), but now this should be zpk([67725], [3225]).
New digital compensation filter was made and the coefficients loaded to SUSETMX and SUSETMY.
Old compensation filter in L3 ESDOUTF antiAcq: zpk([152], [3250], 1, "n").
New one: zpk([3225], [], 1, "n"). The 67kHz
polezero in analog is ignored.Attached is the transfer function from L3 ESDOUTF_LL_IN1 etc. to the LVESDAMON_LL_OUT_DQ etc.
LVESDAMON channels are with correct-ish dewhites mentioned in alog 25471, so they are supposed to be transparent for f<1kHz.
If the new antiAcq filters in the actuation are good, the measured transfer function should be flat, and indeed all TFs measured look flat for 1<1kHz.
The analog and digital filters seem to be the same? I guess the analog TF changed from zpk([3250], [152]) to zpk([67725], [3225]).