Operation of the Maximum Payload Speed Manager
The Maximum Payload Speed Manager compares the actual payload weight on the machine to an overload setting. When the VIMS has determined that the machine is overloaded, the machine is slowed down by limiting the shift range of the transmission and the engine speed is reduced at the limited gear. The payload weight is monitored as the machine shifts to second gear.
Machine Response to the Weight of the Payload
| Conditions and the Corresponding Response of the Machine | |
|---|---|
| Condition | Response |
| The weight of the payload is within the specified limit for the target payload. | No action is taken. The machine will continue normal operation. |
| The weight of the payload is greater than the specified Target Payload Setting but less than the specified Percent Above Payload target. | A machine overload event is recorded.
A machine overload event is broadcast via a radio telemetry system. The VIMS displays messages to the operator. These messages warn the operator that the machine is overloaded and the messages instruct the operator to proceed carefully. |
| Weight of the payload is greater than the specified Percent Above Payload Overload Limit . | An event is recorded for the machine overload limit.
The event for the machine overload limit is broadcast via a radio telemetry system. The VIMS displays warning messages to the operator that the machine is overloaded. A category 2-S warning sounds if the operator proceeds without correcting the overload condition. The VIMS displays warning messages to the operator that machine operation has been limited and the VIMS instructs the operator to resolve the overload condition. The shift range of the transmission is limited. High idle of the engine is limited. The point for automatic retarding is reduced. |
The Maximum Payload Speed Manager will activate the overload events when the weight of the payload exceeds the set limit regardless of the location of the truck. The speed limiting of the machine is activated when the weight of the payload exceeds the set limit regardless of the location of the truck. This behavior will remain active until the payload is dumped and the weight of the payload is cleared. The limiting of the machine speed and the VIMS messages cease automatically after the payload has been dumped. The machine is then returned to normal operation.
The weight of the payload is calculated when the truck is shifted into second gear (second gear weighing). The new weight of the payload that is determined during the second gear weighing is then used to determine if limiting the speed of the machine is necessary.
Once the Maximum Payload Speed Manager has determined that the truck is overload, the following actions are initiated:
- The shift range of the transmission is limited to second gear.
- High idle of the engine is limited to 1750 rpm.
- The point for automatic retarding is reduced to 1750 rpm.
The settings that are listed above are not adjustable.
Example of the Operation of the Maximum Payload Speed Manager
The Project Manager of a site has decided that the normal haul weight for a 793C is 240 tons. The Project Manager has decided that the 793C should never exceed a limit of 288 tons. In order to achieve these objectives the Project Manager would set the parameters of Maximum Payload Speed Manager to the values that are listed below:
Target Payload Setting - 240 tons
Payload Overload Limit Setting - 120% (288/240=120%)
With these settings the Maximum Payload Speed Manager will function in the manner that is listed below:
- The payload loading lamps will load to 240 tons.
- The overload warnings will occur above 264 tons.
- The engine speed will be limited to 1750 rpm in second gear above 288 tons.
- The external payload display will show the current payload weight.
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| Illustration 1 | g00739639 |
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Maximum Payload Speed Manager setup for a 793C Off-Highway Truck | |
Setup of the Maximum Payload Speed Manager
The Maximum Payload Speed Manager requires the user to enter information into the system. This information is used to define the system behaviors that are listed below:
- Overload speed limiting
- Overload events
- Overload warnings
The "target payload setting" is used during payload operations in order to control the operation of the external payload lamps. The "target payload setting" is adjustable from zero to the target weight of the truck that is being setup. The target weight is the maximum weight of payload that is determined from the GMW of the machine. The "target payload setting" is stored in the onboard memory of the VIMS ECM. The "target payload setting" is programmed via the keypad.
The service operation of Payload Configuration (PAYCONF) is used to set this value. Refer to the Systems Operation, "Truck Payload - Configure" section of this manual for instruction on entering this information into the system.
The "payload overload limit" is the maximum payload weight that is allowed before the VIMS will display warning messages to the operator. The VIMS will also limit the speed of the machine, if the payload weight is too high. The "payload overload limit" is adjustable from 105 percent to 120 percent in increments of one percent. The "payload overload limit" is stored in the onboard memory of the VIMS ECM. The "payload overload limit" will allow the user to set the percentage to zero. The system will be disabled when the percentage is set to zero. The default setting is zero percent. The service operation of Payload Configuration (PAYCONF) is used to set this value. Refer to the Systems Operation, "Truck Payload - Configure" section of this manual for instruction on entering this information into the system.
There are two methods available to enter the values for the Target Payload Weight and the Payload Overload Limit.
The first method utilizes the Service Program Code (SPC) of PAYCONF (7292663). Refer to the Systems Operation, "Truck Payload - Configure" section of this manual for instruction on entering this information into the system.
The second method is to use the Electronic Technician software. Use the procedure that is listed below to enter the desire values.
Electronic Technician (ET) Procedure
- Connect the 160-0142 Data Link Cable between the 7X-4401 Communication Adapter and the Service Tool (ET).
- Connect the 139-4166 Data Link Cable between the 7X-4401 Communication Adapter and the diagnostic connector on the machine.
- Turn ON the service tool and open the Electronic Technician application.
- Turn the disconnect switch and the key start switch to the ON position.
Show/hide table
Illustration 2 g00742484 - Click on the "Connect" icon (1) in the tool bar of ET. This will establish communication with the machine and the ET as shown in Illustration 2.
Show/hide table
Illustration 3 g00742500 - Select "VIMS main" from the "ECM Selector" dialog box and click on the OK button. This is shown in Illustration 3. This will display the "ECM Summary" screen.
- Select the "Service" menu.
- Select "Configuration" from the "Service" menu. This will display the "Configuration" screen.
Show/hide table
Illustration 5 g00742543 - Double click on the parameter that you want to change. This will display the "Change Parameter Value" dialog box.
Show/hide table
Illustration 6 g00742546 - Enter the new value of the parameter into the "New Value" text box and then click on the "OK" button. ET will prompt the user with a confirmation message that asks “Are you sure you want to program this parameter?”. Click the "Yes" button if you wish to accept the change.
Note: Repeat this procedure for both Maximum Payload Speed Manager Parameters.
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| Illustration 4 | g00742540 |
The Service program Code ESET (3738) allows the user to modify the behavior of the payload data events that are listed below.
- 2915
- 2916
- 2917
Refer to the Systems Operation, "Event - Configure" section of this manual for instruction on modifying the payload data events.