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Entry  Fri Jan 5 19:19:25 2018, rana, Configuration, SEI, Barry Controls 'air puck' instead of 'VOPO style' breadboard mm_slm.jpgScreen_Shot_2018-01-05_at_7.25.47_PM.png
    Reply  Wed Jan 10 16:27:02 2018, Steve, Configuration, SEI, load cell for weight measurement stacis3LoadCells.png
       Reply  Wed May 2 10:03:58 2018, Steve, HowTo, SEI, preparation of load cell measurement at ETMX 6x
          Reply  Thu May 3 09:56:42 2018, Steve, HowTo, SEI, preparation of load cell measurement at ETMX 
             Reply  Mon May 14 08:55:40 2018, Dennis Coyne, HowTo, SEI, preparation of load cell measurement at ETMX 
    Reply  Tue Jan 23 16:02:05 2018, Steve, Configuration, SEI, load cells stacis3LoadCells.pngDSC00025.JPGDSC00026.JPG
Message ID: 13806     Entry time: Wed May 2 10:03:58 2018     In reply to: 13526     Reply to this: 13809
Author: Steve 
Type: HowTo 
Category: SEI 
Subject: preparation of load cell measurement at ETMX 

Gautam and Steve,

We have calibrated the load  cells. The support beams height monitoring is almost ready.

The danger of this measurment that  the beams height changes can put shear and torsional forces on this formed (thin walled) bellow

They are designed for mainly axial motion.

The plan is to limit height change to 0.020" max

0, center oplev at X arm locked

1, check that  jack screws are carrying full loads and set height indicator dials to zero ( meaning: Stacis is bypassed )

2, raise beam height with aux leveling wedge  by 0.010"  on all 3 support point and than raise it an other 0.005"

3, replace levelling wedge with load cell that is centered and shimmed.     Dennis   Coyne pointed out that the Stacis foot has to be loaded at the center of the foot and formed bellow can shear at their limits.

4, lower the support beam by 0.005" ......now full load on the cells

Note: jack screw heights will not be adjusted or  touched.......so the present condition will be recovered

Quote:

We could use similar load cells   to make the actual weight measurement on the Stacis legs. This seems practical in our case.

I have had bad experience with pneumatic Barry isolators.

Our approximate max compression loads are 1500 lbs on 2 feet and 2500 lbs on the 3rd one.

 

 

Attachment 1: loadcellCAL500.pdf  3.263 MB  Uploaded Wed May 2 11:05:06 2018  | Hide | Hide all
loadcellCAL500.pdf
Attachment 2: 3loadcellwcontr.jpg  2.259 MB  Uploaded Wed May 2 11:06:17 2018  | Hide | Hide all
3loadcellwcontr.jpg
Attachment 3: loadcellLocation.pdf  1.648 MB  Uploaded Wed May 2 11:08:45 2018  | Hide | Hide all
loadcellLocation.pdf
Attachment 4: DSC01009.JPG  1.477 MB  Uploaded Wed May 2 11:10:53 2018  | Hide | Hide all
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Attachment 5: jack_screw.jpg  2.369 MB  Uploaded Wed May 2 15:58:35 2018  | Hide | Hide all
jack_screw.jpg
Attachment 6: ETMX_NW_foot_STACIS.pdf  2.142 MB  Uploaded Wed May 2 17:21:26 2018  | Hide | Hide all
ETMX_NW_foot_STACIS.pdf
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