Foif J2-2, Инструкция по эксплуатации

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3. Index Error
With the instrument in face left, the vertical circle should read 90°00
′
00
″
or
270°00
′
00
″
when the line of sight is horizontal. If it dose not, the deviation is known
as the index error.
To determine the index error:
Level up instrument. With instrument in face right bring horizontal hair onto a well
defined target. Take R reading, repeat in face left and take L reading, then the index
error is determined as:
For example: L = 86°14
′
35
″
R =273°43
′
57
″
Then i = 44
″
Correct value L = 86°15
′
19
″
R = 273°44
′
41
″
For angle measrements with J2-2 theodolite, i of less 15
″
is usually acceptable.
To adjust:
Open cover (4) the adjustment screw for the vertical index is now seen. The