LIGO Document E1500154-x0

DCN: Remove laser diode power monitoring from Optical Lever system

Document #:
LIGO-E1500154-x0
Document type:
E - Engineering documents
Abstract:
Change: Remove laser diode power monitoring from the optical lever system.
HAM Table and Optics levers: from D1002740-v5 to D1002740-v6 (pg 16 changed)
ITMS and BS: from D1100022-v11 to D1100022-v12 (pg 21 changed)
ETMs: from D1002741-v7 to D1002741-v8 (pg 16 changed)

Reason/background: All optical levers have the ability to readout out laser diode power monitors. Readout channels for these monitors were an intended part of the Optical Lever design per these drawings:

HAM Table and Optics levers
https://dcc.ligo.org/LIGO-D1002740, pg 16
ITMS and BS
https://dcc.ligo.org/LIGO-D1100022, pg 21
ETMs
https://dcc.ligo.org/LIGO-D1002741, pg 16

such that we could assess (and perhaps alarm on) the health of the optical lever lasers.

As of Feb-2015 neither observatory has laid the necessary cabling for this system, nor are their channels built into in the SUSAUX front-end code expecting them.

A decision has been made to eliminate the laser diode power monitoring from the baseline design. See integration issue #1017:
https://services.ligo-wa.caltech.edu/integrationissues/show_bug.cgi?id=1017

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