General Tools and Instruments LDM60 - Manual (Page 18)

Fig. 7. A display showing the addition
of a 16.325 ft. measurement to
a measurement of 2.090 feet
To subtract a measurement from an
existing measurement displayed on the
bottom line, press the
button. The
earlier measurement will be moved from the bottom line to the
second line and a flashing
icon will appear at the left of five
dashes (representing the distance value to be subtracted) on the
third line. Then press the
button while aiming the laser at the
point from which the first measurement was made. The meter
will measure the distance to that point, replace the dashes on
the third line with that value, and display the difference of the
two measurements on the bottom line.
Indirect Measurements of Height or Length using
Triangulation
The LDM60 can use triangulation (one type of indirect
measurement based on Pythagorean geometry) to calculate the
height or length of an object from a distance. The meter can
perform two kinds of calculations:
• Triangulation with two inputs. This kind of distance
measurement can be made only for distances that present you
with a right angle. A good example is measuring the height of a
building from across the street at ground level (Fig. 8). Because
the meter and the bottom of the building are both at ground
level, the side of the building (whose height “A” is unknown)
forms one leg of a right triangle whose other leg is the distance
across the street (“B” in the figure). In other words, you can
triangulate the height “A” using only two inputs because “A” is
MEAS
18
16.325
18.415
2.090
➤