TM5-6675-326-14
6-3 TECHNICAL PRINCIPLES OF OPERATION - Continued
6-3.1 Measuring Instruments .
Provide an approximate measurement of a
line or area by translating the movement of measuring instruments during
t r a c i n g i n t o e l e c t r o n i c p u l s e s.
Measurement pulses (counts) are emitted
as long as the measuring instrument is moving.
The pulses (counts) are
sent to the auto-scaler.
There are four measuring instruments:
planimeter, linear measuring probe, point counter pen, and drafting
b r i d g e.
6-3.1.1 Planimeter. Used to trace the perimeter or boundary line of a
p l a n e f i g u r e.
Pulses emitted during tracing are sent to the auto-scaler
and counted. The count is then used in calculating the estimated area or
volume measurement of the figure.
6-3.1.2 Linear Measuring Probe.
Used to measure the length (distance) of
c u r v e d o r s t r a i g h t l i n e s.
The linear measuring probe emits pulses per
unit of length measured.
The pulses are sent to the auto-scaler and
counted. The count is then used in calculating the estimated length or
distance of line measured.
Change 2
6-7
