Introduction
Every site has a defined construction surface based on the engineering design for the project. This is called the design surface.
In the AccuGrade System, the vertical and horizontal guidance information is provided by a design. The design may also contain a background line drawing.
Designs
A design must contain a design surface.
The design surface contains vertical guidance information for a specific area. The design surface can be an irregular surface or a flat plane. The difference in position between the height of the cutting edge of the blade and the height of the design surface, at the same place, is called cut or fill. The software for the AccuGrade System displays the cut or the fill on the light bars and on the Display.
The AccuGrade System uses the design information in order to control the movement of the blade when the automatic controls are enabled.
Note: In some cases, the design surface is a large vertical distance from the current machine position. Use the working surface options to temporarily raise or lower the design surface to a feasible working surface. For more information, refer to Operation and Maintenance Manual, "Vertical Guidance".
Specifying a Design Surface
- 1D design surfaces are specified by creating a physical reference surface
- 3D design surfaces are specified by loading or creating a 3D design file
1D Design Surfaces And Benching
A 1D design surface is defined using the following procedure:
- Establish a reference surface.
For systems using a Sonic Tracer as a lift sensor, build a string line or curb or grade a reference plane. The AccuGrade System will generate cut/fill values that will position the Sonic Tracer so that the distance between the Sonic Tracer and the reference surface remains constant.
- Fix the height of the reference surface, as determined by the lift sensor, relative to a known position of the cutting edge.
This process is known as benching. The position of the cutting edge can be measured against a benchmark, with a known elevation, or relative to the reference surface itself.
- Determine the difference in elevation between the design surface and the benchmark.
This difference is known as the reference elevation. As you work, the offset represented by the reference elevation will reduce to zero.
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| Illustration 1 | g01207166 |
Illustration 1 shows the relationship between the reference surface, in this case an existing curb line, and the benchmark elevation. Because the blade has been placed at the design elevation for benching, the reference elevation will be zero. In operation, the system will generate cut/fill values that will move the blade up and down to maintain a constant distance between the Sonic Tracer and the reference surface.
3D Design Surfaces And Design Files
A 3D design surface is defined by a digital design surface file, or design. A design must contain a 3D design surface and can also contain background linework. The design surface contains vertical guidance information for a specific area. The design surface can be an irregular surface or a plane.
Design surfaces are created in the office and saved onto a data card in the form of a design file. From the data card, the design file can be loaded directly to the Display. A data card can contain more than one design file. However, the AccuGrade System will only load one design at a time for display and guidance.
Note: Once a data card is loaded into the Display, it is recommended that you do not remove the data card until the Display is turned off.
Avoidance zones
A beeper alerts you as the machine approaches an avoidance zone.
Avoidance zones are designated areas that you must keep away from. Avoidance zones can be sitewide, or avoidance zones can be specific to a particular design surface. AccuGrade System provides avoidance zone proximity detection at the blade tips. If the distance from the ripper to the blade has been configured, avoidance zone proximity detection is also given relative to the rippers, and is based on the width of the blade.
Site avoidance zones
When the system is turned on, Site avoidance zones are automatically loaded from the data card. Then, the Site avoidance zones are displayed in the Plan View. Site avoidance zone proximity detection is provided until the Display is turned off.
Note: If the Site avoidance zone cannot be loaded, the Display will be turned off. The data card with the avoidance zone must be removed from the Display in order to continue operation. Contact your site manager immediately.
Design avoidance zones
Design avoidance zones are specific to a design surface. Design avoidance zones load from the data card as the design is loaded.
Design avoidance zones are shown in the Plan View of the Display. Design avoidance zone proximity detection is provided while the design surface remains loaded.
Note: If the Design avoidance zone cannot be loaded, the selected design will not be loaded. Select an alternative design surface in order to continue. Contact your site manager immediately.
No avoidance zone guidance
While any of the following warning messages are displayed, avoidance zone guidance is not given:
- "V. Low Accuracy"
- "No GPS Data (Left)"
- "No GPS Data (Right)"
- "Old Position"
- "No GPS Receiver Data"
- "Invalid GPS" Data
If any of the above messages appear, the following warnings are activated:
- the "NO AVOID " indicator appears on the guidance screens
- the "Avoid. Dist." text item, if configured, appears as N/A
For more information on GPS quality, refer to operation and Maintenance Manual, "Flashing Warning Messages".
Warning Levels
As the machine approaches an avoidance zone, three levels of warning are given.
Note: Your supervisor sets the warning distance for the avoidance zone. This distance can vary with the selected machine type. Ask what the avoidance zone is set to for your machine.
If you are within three times the warning distance, the following warnings are activated:
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| Illustration 2 | g01296067 |
- The avoidance zone becomes filled with a magenta color.
- If configured, the "Avoid. Dist." text item shows the distance and direction to the closest avoidance zone design boundary.
Once you are inside the configured warning distance, the following warnings are activated:
- In the Plan View, the machine icon flashes with a warning symbol.
- The Avoid indicator appears in the bottom right corner of all guidance screens.
- A beeper will beep three times.
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| Illustration 3 | g01296071 |
If you enter the avoidance zone:
- A flashing message informs you that the machine has entered the avoidance zone. The message "Avoid. Zone Entered" has a yellow background. The message appears in all screens.
- A series of beeps sound until you exit the zone.
- The "Avoid. Dist." text item shows a negative value.
- The location where your machine entered and exited the avoidance zone is recorded in the program log.
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| Illustration 4 | g01296254 |
On-screen linework
A design can include on-screen linework. The onscreen linework can include the following background elements:
Note: You can select the following background elements for horizontal guidance. For more information, refer to Operation and Maintenance Manual, "Selecting an Alignment for Horizontal Guidance".
Site Map - The site map provides an outline of the site. When a site map is present on the data card, the site map information loads when you turn on the Display. If the Display is already turned on, the site map information loads when you insert the data card. Site map information is shown in the Plan View.
Background Linework - Background linework is similar to a site map, but background linework information loads and unloads with the selected design. Background linework information is useful for showing perimeters and other areas of interest around the design surface. Background linework information is displayed in the Plan View.
Design Boundary - Most designs have a design boundary which indicates the extents of the vertical guidance information. If you move outside the design boundary, vertical guidance stops.
Road Alignments - Road files describe a road surface by horizontal and vertical alignments. These alignments have had a series of templates or standard cross sections applied.
Accessing designs in the field
In order to enter a design into the AccuGrade System, use either of the following methods:
- a data card
- the keypad
Data card input
Design surfaces are developed in the office and saved onto a data card. From the data card, the design surfaces can be loaded directly to the Display.
A data card can contain more than one design. However, the AccuGrade System will only load one design at a time for display and guidance. For information on how to select a design from the data card, refer to Operation and Maintenance Manual, "System Startup and Shutdown".
Note: Once a data card is loaded into the Display, do not remove the data card until the Display is turned off.
Keypad input
Use the keypad to input simple planes. A simple plane is defined as one of the following surfaces:
- a level surface
- a sloping plane surface with a cross slope
Normally, you would use the keypad to input small on-site designs, such as extra benches, building pads or temporary access ramps.
When you create a design with the keypad, the data card must be in the Display. The data card must also be inserted when you edit a level surface or a sloping surface.
For more information, refer to Operation and Maintenance Manual, "Level Surface Design" or Operation and Maintenance Manual, "Sloping Surface Design".