TM 5-6675-323-14
P r o v i d e an approximate measurement of a line
9-3.1 M e a s u r i n g I n s t r u m e n t s .
or area by translating the movement of measuring instruments during tracing into
e l e c t r o n i c p u l s e s . M e a s u r e m e n t 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 bridge.
a. Planimeter.
Used to trace the perimeter or boundary line of a plane figure.
P u l s e s e m i t t e d d u r i n g t r a c i n g a r e s e n t t o t h e a u t o - s c a l e r a n d c o u n t e d . T h e count is
then used in calculating the estimated area or volume measurement of the figure.
b. Linear measuring probe. Used to measure the length (distance) of curved or
s t r a i g h t l i n e s . T h e linear measuring probe emits pulses per unit of length
measured.
T h e pulses are sent to the auto-scaler and counted. The count is then
used in calculating the estimated length or distance of line measured.
9-7
