keith.thorne@LIGO.ORG - posted 08:04, Tuesday 04 June 2013 - last comment - 11:45, Wednesday 05 June 2013(6611)
MC1 DAC outputs during watchdog trips
I have access the H1 system to examine DAC outputs during the problem with the large M1 offsets (see aLOG entry). Note that DCUID 33 is the IOP model. DCUID 34 is the MC1 model. On MC1, DAC 0 0-5 are used. In the attached plot, you will see that there is indeed activity on the DAC outputs for DCUID=34 (MC1) at the same time the DCUID=33 (IOP) reports it, at least to this observer.
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Eyeballing the offset amplitude in the channels shown in LHO aLOG 6599, the calibrations are: H1:SUS-MC1_M1_OSEMINF_T1_INMON (Open Light Compensation) (ADC) (SatAmp Transimpedance) (unit conversions) (Ideal OSEM Sensitivity) 9000 [ct] * 1.156 [ideal ct/individ ct] * (40/2^16) [V/ct] * (1/240e3) [A/V] * 1e6 [uA/A] * 1e-3 [mm/m] * (0.7/76.29) [ideal m/uA] = 0.00024277 [m] = 243 [um] H1:SUS-MC1_M1_VOLTMON_T1_MON (ADC) (Monitor Board Gain) (TOP Driver Output Admittance) (10D x 5T [mm] Magnet) 11000 [ct] * 40/2^16 [V/ct] * (3/2) [diff V/ s.e. V] * 0.0097693 [A/diff. V] * 0.963 [N/A] = 0.094744 [N] V = 0.094744 [N] * 0.002788 [m/N] (@ DC) = 0.00026415 [m] = 264 [um] R = 0.094744 [N] * 0.059918 [m] * 0.046156 [rad / N.m] (@ DC) = 0.00026202 [rad] = 262 [urad] (Encouragingly, the calibrated OSEMINF and VOLTMON amplitudes agree.) Note: in addition to the links already cited above, I've used a combination of the HAM Triple SUS Controls Design Description, and the information from the output of functions make_OSEM_filter_model(0.001,'HSTS','M1'), and generate_Triple_Model_production(0.001,'hstsopt_metal','/ligo/svncommon/SusSVN/sus/trunk/',false,true)