SUPPORT 2Y8926 - Caterpillar

CAN Communication
Keypad (1), propel lever (6), display (13), engine ECM (14) and machine ECM (9) communicate through a CAN. In order to prevent data loss in the communication lines, termination resistors are required at the ends of the CAN bus. CAN resistors (7) and (8) act as termination resistors. The CAN resistors absorb unwanted noise in the communication system which can result in abnormal machine operation.Differences in materials along the CAN bus can cause data pulses in the bus to reflect back through the bus. This reflection, also known as "jitter", creates unwanted noise in the CAN bus. Jitter in the communication lines between computers can distort the original data signals. The distortion can result in data loss. Data in the CAN bus can also be contaminated with radio frequency interference (RFI). This interference can be caused by a number of devices which operate on or near the machine. RFI creates noise in the communication lines which can also distort the original data signals and cause data loss.Determination of Vibratory System Status
Machine ECM (9) examines input parameters in order to determine if the operating conditions for the vibratory system are met. Each of the following parameters must be met:
The engine must be operating.
The throttle status must be set to ECO mode or to high idle.
The propel system must be enabled.
The status of the vibratory control switch must be set to on.Machine ECM (9) receives engine speed data from engine ECM (14) through the CAN. When the engine is operating, the vibratory system can be enabled.Machine ECM (9) monitors input from the throttle switch-on keypad (1) in order to set the desired throttle status. When the throttle status is set to low idle, the machine ECM will not enable the vibratory system. This statement is valid regardless of the status of the vibratory control switch. When the throttle status is set to ECO mode or to high idle, the vibratory system can be enabled.If the propel system has been disabled for any reason, the machine ECM will disable the vibratory system. When the propel system is enabled, the vibratory system can be enabled.Note: Refer to "Propel System" "Electrical Schematic " (Propel System) for additional information.The vibratory system defaults to the disabled condition at engine startup. In this case, the status of the vibratory control switch-on propel lever (6) is set to off. After the engine has been started, machine ECM (9) monitors the state of the vibratory control switch through the CAN. Each time the operator actuates the vibratory control switch, the machine ECM changes the status of the switch. The first time the switch is actuated, the machine ECM changes the status of the vibratory switch from off to on. Subsequent actuations of this switch cycle the switch status between on and off, and the vibratory system status between enabled and disabled.When machine ECM (9) has determined that the vibratory operating parameters are met, the ECM evaluates the following additional input parameters:
Vibratory mode
Vibratory amplitude
Vibratory frequency, on machines