ENGINE AR-PRIMARY 1802795 - Caterpillar

Power Distribution
Illustration 1 g03325862
Water Spray Electrical Circuit (1) From number "one" water spray pump fuse (2) From number "two" water spray pump fuse (3) From machine ECM number "one" fuse (4) From display and keypad fuse (5) From propel and steer fuse (6) Keypad (7) Propel lever (8) Display (9) Water level sender (10) CAN resistor "1" (11) Number "one" water pump (12) Number "two" water pump (13) Number "two" water pump relay (14) Number "one" water pump relay (15) Machine ECMWhen the electrical disconnect switch is in the ON position, power is delivered to the water spray fuses. Power transfers from number "one" water spray fuse (1) to contact "30" of number "one" water pump relay (14) and from number "two" water spray fuse (2) to contact "30" of number "two" water pump relay (13) .When the main relay is energized, power is delivered to the following locations in the water spray system.
Display and keypad fuse
Propel and steer fuse
Machine ECM number "one" fusePower transfers from display and keypad fuse (3) to contact "1" and contact "5" of keypad (6) and contact "2" of display (8). Power transfers from propel and steer fuse (5) to contact "2" of propel lever (7). Power transfers from machine ECM number "one" fuse (3) to terminal "2", terminal "47", terminal "48", terminal "49" and terminal "50" of machine ECM (15). This voltage provides the wake-up signal and the main power supply to the machine ECM.CAN Communication
After machine ECM (15) receives power, the ECM begins to monitor the CAN bus. Keypad (6) and propel lever (7), display (8), and machine ECM 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 resistor "1" (10) acts as termination resistor. The CAN resistor absorbs 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 (). 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.Input Signals
The controls for the water spray system are on keypad (6), and propel lever (7). The microprocessors in the propel lever and the keypad monitor the status of the following control components and send status information to machine ECM (15) through the CAN bus:
Water spray enable switch
Timer increase switch
Timer decrease switch
Spray mode switch
Propel lever position sensorThe propel lever position sensor and the water spray enable switch are integral to propel lever (7). The water spray mode switch, and the timer switches are