AccuGradeTM - Grade Control System (GPS/ATS/Sonic/Cross Slope) Caterpillar

Introduction

By default, the Vertical Guidance option is available for all configurations of AccuGrade GPS system. Depending on the operator configuration settings for your system, some of the options, soft keys, or views discussed in this manual may not be accessible.

The AccuGrade GPS system uses either one or two vertical guidance points to calculate the cut and fill at the blade tips.

The machine icon in the Plan View and the blade icon in the Cross-section View have green lines that show the vertical guidance point settings.

Vertical Guidance Methods

The vertical guidance of the blade tips is calculated in two different ways. The vertical guidance can determine the cut or fill of the blade from a single vertical guidance point, or the vertical guidance can be determined from dual vertical guidance points. From the vertical guidance point or points, a vertical guidance plane is calculated and projected to the blade tips to calculate cut and fill values.

The blade displayed in the Plan View and in the Cross-section View shows the location of the vertical guidance point (or points) as a green vertical line. The vertical guidance of the blade tips is calculated by determining the cut or fill of the blade at two points.

The flexibility of the vertical guidance method improves guidance so that:

• hanging the blade tip over the crown of a road will not cause the crown to be cut off

• hanging the blade tip over the side slope (batter) will not cause vertical guidance to the road surface to start being erroneously elevated or lowered

• you can cut narrow ditches that are smaller than your blade

• for irregular design surfaces the blade can create a smooth cut

1 Point Vertical Guidance

Illustration 1 shows how the AccuGrade GPS system projects the vertical guidance plane from the single vertical guidance point to the blade tips to determine the cut or fill for the blade tips.

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Vertical Guidance Point

2 Point Vertical Guidance

The vertical guidance of the blade tips is calculated by determining the cut or fill of the blade at two points inset from the blade tips. These two points define a line which is then used to calculate the cut or fill values at the blade tips.

Illustration 2 shows how the AccuGrade GPS system projects the vertical guidance plane from the vertical guidance points to the blade tips in order to determine the cut or fill for the blade tips.

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Vertical Guidance Inset Points

Adjust Cut to Avoid Overcut

The "Adjust Cut to Avoid Overcut" option gives cut/fill guidance that prevents over-cutting. Overcutting occurs when the blade tip cuts through the design surface.

For each vertical guidance mode, you can enable the "Adjust Cut to Avoid Overcut" option. This feature prevents the blade tip guidance from over-cutting the design surface. To enable or disable the "Adjust Cut to Avoid Overcut" option, change the setting from any of the vertical guidance method dialogs.

In order to change the "Adjust Cut to Avoid Overcut" option complete the following steps:

1. Press the "Next" key until the "Adjust Cut to Avoid Overcut" field has focus.

2. Press the Down arrow or the Up arrow in order to change the setting. Select:
   • Yes - to adjust the cut.

   • No - to disable the adjustment.

   The changes are saved as you exit the vertical guidance method selection dialog.

Note: The "Adjust Cut to Avoid Overcut" setting is not specific to the current vertical guidance method. If you make changes to the "Adjust Cut to Avoid Overcut" setting in any vertical guidance dialog, the changes affect all vertical guidance methods.

In order to see when the "Adjust Cut to Avoid Overcut" option is active, configure the "Adjust Cut to Avoid Overcut" text item. The "Adjust Cut to Avoid Overcut" value is the amount that the vertical guidance plane must be raised if the design is not to be overcut. If a value is displayed for the "Adjust Cut to Avoid Overcut" text item, the blade is not following the vertical guidance plane under the vertical guidance points. Check the position of the vertical guidance method selected and reposition your blade.

If you prefer to follow the design surface below the vertical guidance points, disable the"Adjust Cut to Avoid Overcut" option.

Selecting a Vertical Guidance Method

In order to select a vertical guidance method, complete the following steps:

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1. From any guidance screen, press "V. Setup" soft key.

   The Vertical Guidance Setup dialog appears. Refer to Illustration 4.

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2. Press "Change Method".

   A dialog similar to Illustration 5 appears.

3. Highlight the vertical guidance method you want to use.

   Each time you select a method a graphic is presented showing a blade. The blade is drawn as viewed from the machine cab. The green lines on the blade represent the location of the guidance points on the blade. The red solid fill box represents a blade tip with focus.

4. Press the "OK" key to confirm the selection.

Method: "1 Point Center"

The "1 Point Center" method sets one vertical guidance point to the center of the blade. Use this method when you are working on a wide section of the design where the cross slope does not change (for example, the lane of a road). Guidance does not change with respect to the blade tip focus.

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1. Use the arrow keys to highlight the "3D, 1 Point Center" method.

   Refer to Illustration 6.

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2. Press the "OK" key to confirm selection.

   Refer to Illustration 7.

Method: "1 Point Focus"

The "1 Point Focus" method sets one vertical guidance point 0.2 m (0.6 ft) in from the blade tip that has focus. Use this method when you are working on a narrow section of the design where the cross slope does not change (for example, the shoulder of a road). Guidance changes with respect to the blade tip focus.

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1. Use the arrow keys to highlight the "3D, 1 Point Focus" method.

   Refer to Illustration 8.

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2. Press the "OK" key to confirm selection.

   Refer to Illustration 9.

Method: "2 Points Tips"

The "2 Points Tips" method sets two vertical guidance points 0.2 m (0.6 ft) in from each blade tip. Use this method when you are working on an irregular design surface, where the cross slope changes across the width of the blade (for example, a golf course). Guidance does not change with respect to the blade tip focus.

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1. Use the arrow keys to highlight the "3D, 2 Point Tips" method.

   Refer to Illustration 10.

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2. Press the "OK" key to confirm selection.

   Refer to Illustration 11.

Method: "1 Point Custom"

The "1Point Custom" method lets you set one vertical guidance point at a customized distance from the blade tip with focus.

In order to configure the "1 Point Custom" method, complete the following steps:

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1. Use the arrow keys to highlight the "3D, 1 Point Custom" method.

   Refer to Illustration 12.

2. Press the "OK" key to confirm selection.

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3. Press the "NEXT" key in order to highlight a field.

   Refer to Illustration 13.

4. Press the arrow keys in order to enter a value into the field.

   "A" is the horizontal distance from the blade tip with focus to the guidance point. The vertical guidance point will change sides of the blade when the focus point changes. A must be a value between zero and the blade width.

Method: "2 Points Custom"

Use the "2 Points Custom" method when a design surface requires extra control over the positioning of the vertical guidance points along the blade. The "2 Points Custom" method allows you to set two vertical guidance points at specified distances along the blade edge. In order to configure the "2 Points Custom" method, complete the following steps:

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1. Use the arrow keys to highlight the "3D, 2 Points Custom" method.

   Refer to Illustration 14.

2. Press the "OK" key to confirm selection.

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3. Press the "NEXT" key in order to highlight a field.

   Refer to Illustration 15.

4. Press the arrow keys in order to enter a value into the field.

   "A" is the horizontal distance from the blade tip with focus to the guidance point. The vertical guidance point will change sides of the blade when the focus point changes. "A" must be a value between zero and the blade width.

5. Press the "NEXT" key in order to highlight a field.

6. Press the arrow keys in order to enter a value into the field.

7. Press the "NEXT" key in order to highlight the "C" field.

   "C" is the horizontal distance from the blade tip without focus to the second guidance point. "C" must be a value between zero and the blade width minus "A".

   "B" updates automatically.

   Note: B = blade width – (A+C)

8. Press the arrow keys in order to enter a value into the field.

9. Press the "OK" key to save the Vertical Guidance Method.

Method: "Cross Slope"

Use the Cross Slope method when a constant cross slope is desired. In order to configure the "Cross Slope" method, complete the following steps:

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1. Use the arrow keys to highlight the "Cross Slope" method.

   Refer to Illustration 16.

2. Press the "OK" key to confirm selection.

Method: "Lift + Cross Slope"

Use the Lift + Cross Slope method when lift guidance on one tip of the blade and a constant cross slope is desired. In order to configure the "Lift + Cross Slope" method, complete the following steps:

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Illustration 17	g01206644

1. Use the arrow keys to highlight the "Lift + Cross Slope" method.

   Refer to Illustration 17.

2. Press the "OK" key to confirm selection.