evan.goetz@LIGO.ORG - posted 17:51, Monday 08 October 2018 - last comment - 12:52, Wednesday 28 November 2018(44418)
Front end CAL model changes
Jeff K., Evan G. ECR: E1800246 IIET: 11305, 5205 Work permit: 7850 We revised and compiled several front end models with several updates to enable compensation for time dependent interferometer parameters, and general clean-up. We list below the changes: 1) CAL-CS top level model changes: /opt/rtcds/userapps/release/cal/h1/models/h1calcs.mdl - Removed DARM_ERR_WHITENED and DARM_CTRL_WHITENED since these are no longer actually whitened and instead are double precision channels - Added an IPC receiver from each end station TX PD to the top-level CAL-CS model and piped it in to the CS library part - Added new CFTD_DELTAL channels to the frames (CFTD = compensated for time dependence) as parallel channels to the standard DELTAL channels - Deleted DARM hardware injections in top level CAL-CS. These were unused (Note removing whitened channels and DARM hardware injections saves at least five 16k channels from being saved to frames. We added only two 16k channels and four 4k channels) 2) PCAL library changes: /opt/rtcds/userapps/release/cal/common/models/PCAL_MASTER.mdl - Removed oscillator line filters because they were unused - Removed RX and TX_PD_VOLTS filters and replaced with EPICS and testpoints - Implemented computation of optical efficiencies and force coefficients as laid out in T1800046 - Allowed for different ADC gains and different analog AA filter gains because we care about this in the h(t) calibration at the <0.1% level 3) Since LHO alog 44319, we have: /opt/rtcds/userapps/release/cal/common/models/CAL_CS_MASTER.mdl /opt/rtcds/userapps/release/cal/common/models/CAL_LINE_MONITOR_MASTER.mdl - completed the front end computation of the detuned SRC spring frequency and Q (f_s and Q) because we changed the tracking of PUM and UIM stage from a common time dependent scalar to be separately tracked as two time dependent scalars - implemented parallel path calculation for on-the-fly compensation for a time-dependent cavity pole frequency - added excitation point in QUAD model parallel to the calibration lines so that we make excitations for sweeps at the same point as for the calibration lines that are injected. This allows for easier removal of time-dependent changes in actuation gains so that we can search for unknown systematic errors 4) In top level PCALEX / PCALEY model: /opt/rtcds/userapps/release/cal/h1/models/h1calex.mdl /opt/rtcds/userapps/release/cal/h1/models/h1caley.mdl - added IPC senders of TX PD signals to go to the CAL-CS model Presentation given to the calibration group (see G1801594) will be updated to reflect these changes.
Here some screenshots of the updates to the PCAL front-end model and MEDM screens updated to more explicitly calculate the force coefficient used in the pcal system. The screenshots of the simulink model are from the PCAL library part, /opt/rtcds/userapps/release/cal/common/models/PCAL_MASTER.mdl The MEDM screen for the newly explicit calculation of the force coefficient can be found from each PCAL overview screen (see 4th image), by following the "Filt. Calibrated" linked screen button (third down from the list of three linked boxes in the upper right corner). The 5th attachment is this new screen (crafted by Evan), and the former old calibration filters can be found linked from this screen in the lower right corner, labeled "SUS m/N." These screens live in /opt/rtcds/userapps/release/cal/common/medm/ PCAL_END.adl PCAL_END_FORCE_COEFF.adl PCALFastFilterCal.adl At the moment, all of this new infrastructure is bypassed as shown in the attached screenshots. This is done by setting virtually all the new EPICs records to 1.0, and the cos( heta) term to be 1/2 * c, such that when the hard-coded speed of light is multiplied in, this previous term cancels it to be 1.0 as well. As such, the TX_PD or RX_PD filters -- which in the new scheme are intended to be only the suspension response (currently in FM6 and FM8 as "susnorm" and "m_per_N") -- still include the O2 force coefficients in FMs 1 and 2 as "cts2V" and "N/V".