CCF LinCoord holds the positions of distinct reference points of the CCD's (at reference temperature) and the directions in which the counting of rawX and rawY increases. The size of each pixel is stored in CCF MiscData, and also a thermal expansion coefficient.
Using these inputs, together with (rawX,rawY), the location of each pixel can be given in focal plane coordinates as a function of temperature. The shift of CCD's due to thermal contraction/expansion is calculated such that each CCD is fixed with its center on the cold bench, and the pixel-size is determined from the thermal expansion coefficient of Si.