Easson ES-9Q, Operation Manual, Page: 41 / 56

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Non-linear error compensation
Using a high magnification lens ( 50X or 100X) to locate the most negative position of the glass scale, positive the cross hair of
the screen to the first line of the glass scale, record down this position as the CP. START position.
Because the CP. START position
always in the most negative position
of the projector trave, therefore, it
should always be negative value
record down this position by pen,
i.e., the CP.START= -90.565
3) Start measure the errors to build up an error curve
To make the error measurement more easy, swap to INC coordinate and zero at the CP. START position
swap to INC coordinate
zero at the CP. START
position in INC coordinate
start measure the error by positioning
the cross hair of screen on the glass
scale. Take down the display value
shown at the readout and compare
it with the glass scale grating.
Polar
XY
Store
Recall
R/D
Print
Enter
Q
FINISH
ABS
-90.565
Polar
XY
Store Recall R/D Print
Enter
Q FINISH
INC
Polar
XY
Store Recall R/D Print
Enter
Q FINISH
ABS
Polar
XY
Store Recall R/D Print
Enter
Q FINISH
INC
0.000