= KAGRA VIS Operations Manual - LVDT =
<<TableOfContents(3)>>
LVDTs are used for vertical sensing and actuation in all the GAS filters and for horizontal sensing and actuation in all the IP stages.

See [[attachment:LVDT Signal Conditioning.pdf|LVDT Signal Conditioning]] for useful background on LVDT demodulation.

See [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=1255|JGW-T1201255]] for description of the Nikhef-supplied cards, and [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=4798|JGW-T1604798]] for more information on how to tune the demodulation circuit.

LVDT Calibration Procedure: [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=7287|JGW-E1707287]] or [[attachment:LVDT_Calibration.pdf| LVDT Calibration Procedure]].

== LVDT Coil and Driver Data ==
||[[KAGRA/Subgroups/VIS/OpsManual/TypeA|Type A]]||Test Mass Suspensions||
||[[KAGRA/Subgroups/VIS/OpsManual/TypeB|Type B]]||BS and SR suspensions ||
||||[[KAGRA/Subgroups/VIS/OpsManual/TypeB/BSData#lvdt|BS Data]]||
||||[[KAGRA/Subgroups/VIS/OpsManual/TypeB/SR2Data#lvdt |SR2 Data]]||
||||[[KAGRA/Subgroups/VIS/OpsManual/TypeB/SR3Data#lvdt |SR3 Data]]||
||||[[KAGRA/Subgroups/VIS/OpsManual/TypeB/SRMData#lvdt |SRM Data]]||
||[[KAGRA/Subgroups/VIS/OpsManual/TypeBp|Type Bp]]||PR Suspensions||
||[[KAGRA/Subgroups/VIS/OpsManual/TypeC|Type C]]||Modecleaner Suspensions||


=== Yoke Height Settings ===
The yoke should be set so that the double and single LVDT coils are symmetrically aligned when the keystone is at nominal height. It is convenient to set this in terms of the amount the PEEK coil former sticks out above the filter baseplate.

==== Bottom Filter (BS and SRx) ====

Note that the CAD is wrong for the bottom filter yoke:

{{attachment:YokeHeightExample.png| |width=400}}{{attachment:KeystoneHeightExample.png| |width=400}}

=== Standard Filter (BS and SRx) ===

{{attachment:YokeHeightExampleSF.png| |width=400}}

=== Top Filter (BS and SRx) ===

{{attachment:YokeHeightExampleBSF0.png| |width=400}}{{attachment:YokeHeightExampleSRF0.png| |width=400}}

==== Summary ====

||GAS Filter||Yoke Height||Keystone Height||
||BS BF||3.5 mm||65.5 mm (up from baseplate)||
||SR BF||3.5 mm||65.5 mm (up from baseplate)||
||BS SF||6 mm||65.5 mm (up from baseplate)||
||SR SF||6 mm||65.5 mm (up from baseplate)||
||BS F0||36 mm||153 mm (up from top plate), 16.5 mm (down from ring)||
||SR F0||34 mm||151 mm (up from top plate), 16.5 mm (down from ring)||

== Type Bp Data ==
Your data here!

<<Anchor(stocktake)>>
= Stocktake =

[[LVDT20180413|Old: LVDT Stocktake as of 2018-04-13]]

== List of LVDT Driver Boxes ==
[[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=2826|LVDT Driver Module Top Assembly]]

=== Currently used drivers ===

==== Type-A ====
||Suspension||Rack||S-Number||Note||
||ETMX || ||[[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=????|S140????]]||LVDT 1||
||ETMX || ||[[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=????|S140????]]||LVDT 2||
||ETMY || ||[[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=????|S140????]]||LVDT 1||
||ETMY || ||[[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=????|S140????]]||LVDT 2||
||ITMX || ||[[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=????|S140????]]||LVDT 1||
||ITMX || ||[[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=????|S140????]]||LVDT 2||
||ITMY || ||[[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=????|S140????]]||LVDT 1||
||ITMY || ||[[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=????|S140????]]||LVDT 2||

==== Type-B ====
||Suspension||Rack||S-Number||Note||
||BS || ||[[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=????|S140????]]|| ||
||SRM || ||[[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=????|S140????]]|| ||
||SR2 || ||[[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=????|S140????]]|| ||
||SR3 || ||[[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=????|S140????]]|| ||
==== Type-Bp ====
||Suspension||Rack||S-Number||Note||
||PRM || ||[[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=????|S140????]]|| ||
||PRM || ||[[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=????|S140????]]|| ||
||PR2 ||PR2||[[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=3047|S1403047]]||For GAS filters ?||
||PR2 ||PR2||[[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=3050|S1403050]]||For BF damper ?||
||PR3 || ||[[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=????|S140????]]|| ||
||PR3 || ||[[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=????|S140????]]|| ||
==== AOS ====
||Suspension||Rack||S-Number||Note||
||ETMX TMS|| ||[[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=????|S140????]]|| ||
||ETMY TMS|| ||[[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=????|S140????]]|| ||

=== Drivers in stock ===
||Location||S-Number||Note||
||Electric shop||[[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=7792|S1407792]]||To be used for ???. OSC circuit is not installed||

=== Broken ===
||Location||S-Number||Note||
||Electric shop||[[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=7786|S1407786]]||||

== LVDT cards ==
 * Number of Input Cards in stock: ??
 * Number of broken input cards (taken out of the driver chasis): ??
 * Number of Mainboards in stock: ??
 * Number of broken Mainboards: ??