Topcon mmGPS 3D Paver, Reference Manual

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Control Methods
P/N 7010-0781
5-29
Sonic Control
The Sonic Tracker II™ measures and controls the elevation of the
machine, controlling grade from a physical grade reference, such as a
curb, stringline, or existing road surface.
The Sonic Tracker II sends out sound pulses 39 times per second. As
soon as the Tracker sends out a sound wave, it starts a stop watch.
The sound waves go down, bounce off of a physical reference, and
reflect back to the Tracker. The Tracker measures the time it takes for
the sound wave to return to the Tracker. Knowing the speed of sound,
the Tracker accurately calculates the exact distance to the grade
reference (Figure 5-22).
• When the Tracker is on-grade, the cutting drum is at the desired
depth.
• If the cutting drum and Tracker start to raise, the Tracker and
control box indicate a down correction arrow, and the lower
hydraulic valve corrections bring the Tracker back on-grade.
• If the cutting drum and Tracker start to lower, the Tracker and
control box indicate a raise correction arrow, and the raise
hydraulic valve corrections bring the Tracker back on-grade.
Figure 5-22. Sonic Tracker II Control
See Chapter 6 for more details about using a sonic sensor as the
control method at the jobsite.
Son
ic Tr
acker
II
Son
ic T
racker
II