Diagonalize the DRMI Length Control
This procedure describes how to measure and invert the input matrix for the 3x3 plant in the DRMI. This is necessary to prevent cross-coupling between the 3 control loops.
It's necessary to redo this procedure anytime there is fiddling with the Mach Zehnder or the Marconi signal generators that provide our modulation frequencies.
This procedure won't work on a solaris machine
This should be run while the DRM is locked & aligned
In the $SCRIPTS/LSC directory, run
setDDphases
This will servo the DD phases to zero, so there will be no offset at the operating point. After that script finishes, run
senseDRM
This will measure the plant, giving you info along the way and putting the results into some files. The last line of screen output should give you something like:
Your command to copy and paste into a terminal is: tdswrite C1:LSC-ITMTRX_92 -1.1198 \ C1:LSC-ITMTRX_b2 2.8519 \ C1:LSC-ITMTRX_d2 -0.17059 \ C1:LSC-ITMTRX_f2 0.28573 \ C1:LSC-ITMTRX_122 -0.089699 \ C1:LSC-ITMTRX_142 -0.065893 \ C1:LSC-ITMTRX_95 0.30456 \ C1:LSC-ITMTRX_b5 -0.69205 \ C1:LSC-ITMTRX_d5 0.046096 \ C1:LSC-ITMTRX_f5 -0.074476 \ C1:LSC-ITMTRX_125 0.022033 \ C1:LSC-ITMTRX_145 0.0052107 \ C1:LSC-ITMTRX_93 -1.3128 \ C1:LSC-ITMTRX_b3 2.6644 \ C1:LSC-ITMTRX_d3 -1.5412 \ C1:LSC-ITMTRX_f3 -0.82075 \ C1:LSC-ITMTRX_123 -0.49044 \ C1:LSC-ITMTRX_143 0.070841 \ C1:LSC-ITMTRX_33 0 \ C1:LSC-ITMTRX_42 0 \ C1:LSC-ITMTRX_155 0
You can copy & paste this command into a terminal to load the new input matrix values.