770, 772, 773E, 773F, 777E and 777F Off-Highway Trucks and 775F Quarry Truck VIMS Truck Payload System Caterpillar

Caterpillar's 10/10/20 rule states “that no more than 10 percent of the payloads may exceed 1.1 times the target payload of the truck and no single payload shall exceed 1.2 times the target payload of the truck”. The Maximum Payload Speed Manager provides the customer with a way to comply with the 10/10/20 rule. This method limits the performance of the machine. The performance of the machine is limited when the weight of the payload is greater than 1.2 times the target payload. When the weight of the payload is 1.2 times the target payload, the brakes and steering are at the maximum levels. Limiting the performance of a machine that is overload protects the machine and the operator. The operator of the loading tool is also forced to load the machine correctly.

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/TPMS 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

Table 1

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 for the machine overload limit is recorded. An event for the machine overload limit is broadcast via a radio telemetry system. The VIMS/TPMS 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/TPMS 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/TPMS messages cease automatically after the payload has been dumped and the machine is returned to normal operation.

The weight of the payload is calculated as the truck is shifted into second gear. This is the 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 for a site has decided that a 777F will normally haul loads of 100 tons and the loads should never exceed a limit of 120 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 - 100 tons

Payload Overload Limit Setting - 120% (120/100=120%)

With these settings, the Maximum Payload Speed Manager will function in the manner that is listed below:

• The payload loading lamps will load through 100 tons.

• The overload warnings will occur above 110 tons.

• The engine speed will be limited to 1750 rpm in second gear above 120 tons.

• The external payload display will show the current payload weight.

Illustration 1	g01293584
Maximum Payload Speed Manager setup for a 777F 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

Target payload

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 Gross Vehicle Weight 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 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.

Payload Overload Limit

The "payload overload limit>" is the maximum payload weight that is allowed before the Messenger/Advisor 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/TPMS 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 is used in order 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.

Methods of System Setup

The value for the Target Payload Weight and the value for the Payload Overload Limit can be entered with the following two methods:

1. The first method utilizes the Messenger/Advisor or selection in the menu. Refer to the Systems Operation, "Truck Payload - Configure" section of this manual for instruction on entering this information into the system.

2. The second method is the use of Cat Electronic Technician (ET) software. Use the procedure that is listed below in order to enter the desired values.

   1. Connect the 160-0142 Data Link Cable between the 7X-4401 Communication Adapter and the Cat ET service tool.

   2. Connect the 139-4166 Data Link Cable between the 7X-4401 Communication Adapter and the diagnostic connector on the machine.

   3. Turn the service tool ON and open the Cat ET.

   4. Turn the disconnect switch and the key start switch to the ON position.
      Show/hide table

      Illustration 2	g01309000

   5. Click on the "Connect" icon (2) in the tool bar of Cat ET. This connection establishes communication between the machine and Cat ET. This connection is shown in Illustration 2.
      Show/hide table

      Illustration 3	g00742500

   6. Select "VIMS main" or "Payload Control" 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.

   7. Select the "Service" menu.

   8. Select "Configuration" from the "Service" menu. This will display the "Configuration" screen.
      Show/hide table

      Illustration 4	g00742543

   9. Double click on the desired parameter. Double clicking will display the "Change Parameter Value" dialog box.
      Show/hide table

      Illustration 5	g00742546

   10. Enter the new value of the parameter into the New Value dialog box. Then click on the "OK" button. Cat ET will prompt the user with a confirmation message. The confirmation message is displayed in order to confirm the desired parameter. Click the "Yes" button in order to accept the change.

       Note: Repeat this procedure for both Maximum Payload Speed Manager Parameters.

Event - Configure (ESET)

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.

Note: VIMSpc must be connected in order to enable the functionality of the keypad.