Automatic Grade Control Sonic Slope

Automatic Grade Control Sonic Slope

  • Bobcat® automatic grading solutions deliver more accurate grading results with less time and labor. 
  • Increase efficiency and reduce fatigue without having to focus on the blade position. 
  • Near-perfect accuracy eliminates the need for a crew to continually check grade. 
  • With accuracies better than +/- ¼-inch, automatic grade control systems can save on expensive finishes such as concrete. 

Features & Benefits

Top Tasks

  • Accurate finish grading 
  • Efficient rough grading 
  • Path construction (golf cart, bike trails, etc.) 
  • Concrete flatwork 

How It Works

Sonic/slope systems have three main components: 

  • The Sonic tracer controls the elevation of that side of the moldboard 
  • The Cross-slope sensor, mounted to the back of the moldboard, maintains a set cross-slope on the opposite side of the moldboard. 
  • The deluxe instrumentation panel is used to operate the system 

Two auxiliary components, including a rotation sensor and main fall sensor, provide correcting information to the slope sensor when traveling up or down hills or when the blade is angled. 

The operator places the sonic tracer over the top of the object he wishes to use as a reference and sets the blade depth as needed.

For example: An operator prepares the sub grade for a road in which the curb and gutter has already been poured. The operator sets the sonic tracer above the gutter and sets the cutting edge of the moldboard 6 in. below that point. The operator then “zeros” the sonic tracer using the Deluxe Instrumentation Panel. Since roads are typically crowned, the operator enters a 1% slope using the Deluxe Instrumentation Panel. After clicking a button on the loader control handles, the system is in automatic mode and the operator starts driving the machine. The blade maintains a depth of 6 in. below the curb at a 1% slope going up toward the center of the road.

The system is also capable of operating only the cross-slope in automatic mode. The operator disables the sonic tracer and manually controls the side of the blade on which the sonic tracer is mounted, while the cross-slope sensor automatically maintains the correct cross-slope across the blade. This is especially useful when making first passes to provide a smooth surface for the sonic tracer to follow on the next pass.

Required Components

  • Sonic Tracer: Mounted on either side of the moldboard, the sonic tracer uses ultra sonic signals to maintain a distance between it and an object below such as a stringline, previous pass, or curb and cutter. The sonic tracer only moves the elevation cylinder for the side of the blade on which it is mounted.
  • Cross-Slope Sensor: This sensor moves the opposite side of the blade to maintain a set cross slope that was entered by the operator. The cross-slope sensor only moves the elevation cylinder on the opposite side of the sonic tracer.
  • Deluxe Instrumentation: The panel allows the operator to set the parameters of the grading system while providing real-time information such as distance-to-target for both elevation and slope. The panel saves money and valuable cab space.

Compatible Models


WARNING: This product can expose you to chemicals including engine exhaust (including diesel engine exhaust when equipped), lead and lead compounds, mineral oils, soots, phthalates, and carbon monoxide which are known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to

Certain specification(s) are based on engineering calculations and are not actual measurements. Specification(s) are provided for comparison purposes only and are subject to change without notice. Specification(s) for your individual equipment will vary based on normal variations in design, manufacturing, operating conditions, and other factors.