Pentax R-315(N) - Manual (Page 75)

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10 CHECKS AND ADJUSTMENTS
10-8 Offset Constant
The offset constant rarely changes. It is recommended, however, that check be
done once or twice a year.
The check of the offset constant can be done on a certified base line. It can also
be obtained in a simple way as described below.
Checks
1. Locate points A, B and C at about 50m intervals on even ground.
2. Set up the instrument at point A, and measure the distances between AB and
AC.
3. Set up the instrument at point B, and measure the distance BC.
4. Obtain the offset constant (K):
K=AC - (AB+BC)
Adjustments
● Contact your local dealer for adjustment of the off-set constant when the K is
not nearly 0.
Instrument Prism Prism
Instrument Prism
A B C
A B C
PENTAX R-300 (p65-88) 10/30/02 11:11 AM Page 73