Reports until 17:02, Tuesday 23 July 2013
H1 ISC
jeffrey.kissel@LIGO.ORG - posted 17:02, Tuesday 23 July 2013 - last comment - 18:44, Tuesday 23 July 2013(7187)
ALS Calibrated Cavity Length Channel 
For future reference,

The calibrated channel representing the frequency of the green laser (in [Hz]) is
H1:ALS-Y_REFL_CTRL_OUT_DQ


This can be converted to the length of the arm cavity using the free spectral range,
Cavity Length = lambda * (L / c) * H1:ALS-Y_REFL_CTRL_OUT_DQ
Comments related to this report
stefan.ballmer@LIGO.ORG - 18:44, Tuesday 23 July 2013 (7192)
Link 

Careful: Since we implemented a bypass path from the PDH board to the laser, there is 22dB less signal on H1:ALSY_REFL_CTRL_OUT_DQ (the fast slider on the Sigg board is at -22dB, since this signal is now goint to the laser).

This means that the calibration has to be corrected by these 22dB. See elog 6900.