Differences between revisions 46 and 47

KAGRA VIS Operations Manual - LVDT

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 LVDT Signal Conditioning for useful background on LVDT demodulation.

See JGW-T1201255 for description of the Nikhef-supplied cards, and JGW-T1604798 for more information on how to tune the demodulation circuit.

LVDT Calibration Procedure: JGW-E1707287 or LVDT Calibration Procedure.

LVDT Coil and Driver Data

Type A	Test Mass Suspensions
Type B	BS and SR suspensions
BS Data
SR2 Data
SR3 Data
SRM Data
Type Bp	PR Suspensions
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:

Standard Filter (BS and SRx)

Top Filter (BS and SRx)

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!

Stocktake

Old: LVDT Stocktake as of 2018-04-13

List of LVDT Driver Boxes

LVDT Driver Module Top Assembly

Currently used drivers

Suspension	Rack	S-Number	Note
PR2	PR2	S1403047	For GAS filters ?

Drivers in stock

Location	S-Number	Note
Electric shop	S1407792	To be used for ???. OSC circuit is no installed

Broken in stock

Location	S-Number	Note
Electric shop	S1407786

KAGRA/Subgroups/VIS/OpsManual/LVDT (last edited 2018-09-14 17:27:24 by YoichiAso)

-  ⇤ ← Revision 46 as of 2018-09-14 16:53:02 → 
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+   ← Revision 47 as of 2018-09-14 16:55:04 → ⇥
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-=== Actively used drivers ===
+=== Currently used drivers ===
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-||Electric shop||[[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=7792|S1407792]]||To be used for ???||
+||Electric shop||[[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=7792|S1407792]]||To be used for ???. OSC circuit is no installed||

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