Operational practice for the best accuracy
Follow the below practices for best accuracy and smooth grade flow:
- Run the machine smoothly without any abrupt starts or stops.
- If operating on a rough surface, drive slow enough to prevent tire bounce.
- Operating at slower speeds provides more precise cross slope control. Experimentation may be necessary to find the right speed at your site.
- Operate with no wheel lean, articulation, blade cushion feature, or circle side shift. These conditions will cause cross slope error.
Note: The blade cushion feature will affect the quality of the grade, when it is enabled.
- Maintain the proper and correct tiers pressure, refer to the manufacturing specification and maintenance manual of the machine.
- Calibrate the Cross Slope system properly if needed, ensure that there is no active (FMI13) failure mode of any of the Cross Slope Sensors (system out of calibration).
Refer to Calibration section of this document for more details.
Note: The inactive automatic control state may occur when the operator attempts to enable the automatic controls by pressing and releasing the auto/manual switch. The auto icon will flash at a rate of times two per second which indicate inactive automatic state (Cross Slope System control temporary unavailable).
Condition for the Cat Grade Control Cross Slope System to be operational
Before operating the Cross Slope sensor, check that the following conditions is true:
- Operator is seated.
Note: The implement ECM monitors the input of the machine seat switch and implement will disable the cross slope system, if the operator is not seated
- Engine is running.
- Parking break is disengaged.
- Implement lock switch is disabled.
Note: Implement ECM monitors the implement lock out switch output, if the lock out switch is enabled the Cross Slope System will be disabled.
- Display must be in one of the two cross slope screens.
- No active diagnostic on a required input or output is present.
- System has no active codes or events.
Refer to Diagnostic Trouble Codes section of this document if any code or event is active.
The factors which affect the quality of the grade are given below:
- Soil Type
- Machine Speed
- Amount of cut
The operator can accomplish the desired grade by adjusting the valve speed (by slowing or speeding up the response of the automatic control system). By adjusting the valve speed, the operator can overcome the three factors that are listed above.
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| Illustration 1 | g06067806 |
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Grade profile | |
The unstable grade may be a result of improper blade reaction time of the valve speed. Unstable grade may cause short waves in the materials, if the valve speed is too high (over correcting the blade movements) or long rolling waves in the materials, if the valve speed is too slow (not correcting the blade movement fast enough) as shown in Illustration 1.
Blade reaction time adjustment
Use the machine display "valve speed" menu to adjust the response time of the valve to reach the desire grade. Decrease the valve speed if the Cross Slope is over correcting (short wave in the material). Increase the valve speed if the valve speed is too slow or not correcting fast enough (long rolling material or grades). Refer to Illustration 1. The procedure to adjust the valve speed on the different types of display are explained below:
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| Illustration 2 | g06067810 |
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| Illustration 3 | g06067812 |
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| Illustration 4 | g06067817 |
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| Illustration 5 | g06067819 |
Go to "performance screen" menu, select "cross slope" > "Target slope" > press the arrow down or up, select "valve speed" adjust the valve speed. Refer Illustration 2, Illustration 3, Illustration 4, and Illustration 5.
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| Illustration 6 | g06067824 |
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| Illustration 7 | g06067826 |
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| Illustration 8 | g06067829 |
Go to "setting menu 2", select "Cross Slope" > "valve speed" > adjust the valve speed. Illustration 6, Illustration 7, and Illustration 8.
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| Illustration 9 | g06067833 |
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| Illustration 10 | g06067842 |
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| Illustration 11 | g06067846 |
Go to "machine menu" > "machine setting" > "cross slope" > "valve speed" > used the increment/decrement bar to adjust the valve speed percentage. Press the (+) button on the right end of the bar to increase the percentage. Press the (-) button on the left end of the bar to decrease the percentage. Refer to Illustration 9, Illustration 10, Illustration 11.
Note: The number will appear in yellow text while setting. The newly set number will appear in white text. Press "ok" button to set and the "back" button to return to the pervious menu.
Refer to media System Operation Troubleshooting Testing and Adjusting, UENR5919, "16M3 and 18M3 Motor Graders Information Display" for step by step procedure on how to adjust the valve speed on the machine display.
Note: The Valve Speed setting is used to adjust the responsiveness of the Cross Slope System when controlling the blade. A higher value will cause the system to react faster. A lower number will cause the system to react slower.
The probable causes for the failure of grade accuracy are given below:
An accuracy problems or uneven grade could be the result of excessive wear to the cutting edge of the Blade.
To check the cutting edge of the blade for excessive wear or uneven edges. Use a string line, by running it from one end of the blade tip to the other end, you can tell if the cutting edges are uneven. The string should be relatively level with the cutting edge. Check the moldboard for straightness. The line of bolts that hold the cutting edge to the blade or moldboard should be straight.
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| Illustration 12 | g06069744 |
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(1) Outermost hole
(2) Outermost hole | |
Run a string line across the moldboard holes. The string line should go from Point (1) to Point (2) or the two outermost holes. The tolerance for the holes is
Excessive play of the blade and circle could cause an accuracy problems or uneven grade.
Check the blade and circle for worn shims. Replace the worn shims.
Refer to the System Operation Troubleshooting Testing and Adjusting, UENR1797, "Cat® Grade Control Cross Slope for Motor Graders".
Cross Slope System Sensors out of calibration
Visually inspect the sensors to ensure that all the bolts used to secure the Cross Slope System sensors are in place and the sensors are secured to the mounting brackets.
Cutting and rewelding or relocating the Blade rotation sensor bracket may cause accuracy issues.
Realign the Cross Slope System sensor that was not secured or relocated. Secure the Cross Slope System sensor to the machine bracket and perform sensor calibration, refer to the Testing and Adjusting manual for more details.