J. Kissel, S. Ballmer Upon receiving a review from Stefan, who agrees that I've interpretted his methods correctly to arrive at the proposed change to the OMC DCPD SUM and NULL balance matrix in yesterday's LHO:68360, I have now installed that 2024-04-03 proposal for the OMC DCPD balance matrix from that aLOG, MM_proposed = 0.99455 1.0055 0.98259 -1.0177 via the command line, $ caput H1:OMC-DCPD_MATRIX_1_1 0.99455; caput H1:OMC-DCPD_MATRIX_1_2 1.0055; caput H1:OMC-DCPD_MATRIX_2_1 0.98259; caput H1:OMC-DCPD_MATRIX_2_2 -1.0177 Old : H1:OMC-DCPD_MATRIX_1_1 1.01039 New : H1:OMC-DCPD_MATRIX_1_1 0.99455 Old : H1:OMC-DCPD_MATRIX_1_2 0.98961 New : H1:OMC-DCPD_MATRIX_1_2 1.0055 Old : H1:OMC-DCPD_MATRIX_2_1 0.98961 New : H1:OMC-DCPD_MATRIX_2_1 0.98259 Old : H1:OMC-DCPD_MATRIX_2_2 -1.01039 New : H1:OMC-DCPD_MATRIX_2_2 -1.0177 Checking the answer... $ caget H1:OMC-DCPD_MATRIX_1_1 H1:OMC-DCPD_MATRIX_1_2 H1:OMC-DCPD_MATRIX_2_1 H1:OMC-DCPD_MATRIX_2_2 H1:OMC-DCPD_MATRIX_1_1 0.99455 H1:OMC-DCPD_MATRIX_1_2 1.0055 H1:OMC-DCPD_MATRIX_2_1 0.98259 H1:OMC-DCPD_MATRIX_2_2 -1.0177 Attached are screenshots of the new values within the MEDM screen, and the acceptance of these values in both the safe.snap and OBSERVE.snap files. A note (just because MEDM matrices can be confusing): ( SUM ) ( DCPDA_1_1 DCPDB_1_2 ) ( DCPDA ) ( ) = ( ) ( ) ( NULL) ( DCPDA_2_1 DCPDB_2_2 ) ( DCPDB ) or SUM = DCPDA_1_1 * DCPDA + DCPDB_1_2 * DCPDB = 0.99455 * DCPDA + 1.0055 * DCPDB NULL = DCPDA_2_1 * DCPDA + DCPDB_2_2 * DCPDB = 0.98259 * DCPDA - 1.0177 * DCPDB This means, for the SUM, which eventually becomes DARM_ERR, the coefficients that form the SUM have changed by :: (0.99455 - 1.01039)/ 0.99455 = -0.0159 = -1.6% for DCPDA and :: (1.0055 - 0.98961)/ 1.0055 = +0.0158 = +1.6% for DCPDB which I think we can safely attribute all changes in the balance to be due to the changes in the DCPD readout electronics (since this matrix hasn't been updated since O3, prior to the replacement/upgrade of the transimpedance amplifier, the whitening chassis, the [lack of] anti-aliasing chassis, and the new ADC.).