tie down Position vs platform position and temp (2002)

feb 2003

The 2002 td,distomat data was passed through the filter:

tension difference pair of cables less than 4 kips

temperature 60 to 95F

height within .4 feet of 1256.35

kips per cable between 5 and 65 kips.

carriage house at stow.

platform height at least .01 feet from 1256.35 (most points are here).

Tiedown Inches motion per platform Inch of Motion.

The data was binned in temperature 70 to 85 deg F (1 deg F wide). Fits were made to the function: avgTdPos=c0+c1*(platformHght-1256.35)*12 at constant temp. The plots show the change in tiedown height versus change in platform height for these temperatures:

Figure 1 plots average tiedown height vs platform offset (inches) from 1256.35 feet for temperatures 70,75, and 80 F
Figure 2 Top plots tdInches/platformInch (c1) versus temperature. The average and a second order fit to temp is shown.
Figure 2 Bottom plots tdPos vs Temp for platform height of 1256.35. This is the avg tiedown position for the focus position.

Historically we have been using -1.77 tiedown inches per platform inch. This was measured back in the year 2000 at a single temp.

summary:

Parameter	constraint	fit
tdIn/Platform Inch:-1.73 tdIn/plIn (avg 70-85F)	constant temp	-1.718+.012722t-.001664t^2 (t=temp-73F)
tdInch/degF: -.3512	constant PlHght 1256.35 used	tdPosAtFocus: 11.9628-.3512*(temp-73F)
plInch/degF: .203 (using .3512/1.73)

processing: x101/td/2002/yr2002Fit.pro

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