P-32+ and P-32 Operator’s Manual P/N: 1001547-01
Standard Topcon P-32+ and P-32 Systems include two Control Boxes, two Sonic Trackers (ST-3 for P-32+ and
Sonic Tracker I I for P-32) and a single Dual Port Slope Sensor. When setup and connected, the Control Boxes
control either the left or right side of the machine for either elevation or slope.
GC-35 Control Box
The GC-35 Control Box (Figure 3) is the operator’s interface to the Topcon P-32 System. The Control Box
receives signals from the sensors (Sonic Tracker, Laser Tracker, and/ or Slope Sensor), and uses these signals to
determine if grade or slope corrections are necessary. I f a change in grade or slope is required, the Control Box
sends a signal to the valve controlling the tow point cylinder on the appropriate side of the machine to raise or
lower, thus maintaining correct mat thickness.
The Control Box connects to the Sonic Tracker, the Slope Sensor, and to the paver through electrical cables. The
Control Box easily attaches to its mounting bracket with one clamp, and at the end of the day should be removed
Figure 3: Control Box
Whether you are using the ST-3 (P-32+ ) or the Sonic Tracker I I (P-32), the Sonic Tracker (Figure 4) measures
and controls the elevations of the screed. A transducer(s), located in the bottom of the Sonic Tracker, generates
sound pulses like a speaker and listens for returned echoes like a microphone. The Tracker measures the
distance, and controls grade from a physical grade reference, such as a curb, stringline, or existing road surface.
A bail is used to compensate for rapid air temperature changes. In paving applications a bail should always be