BOX AS-CONTROL 2248725 - Caterpillar

The implement pressure sensor sends an input signal to the machine ECM. When the joysticks are moved from the NEUTRAL position for a boom UP, stick IN, stick OUT, bucket IN, or a bucket OUT operation, pilot oil is directed to the implement pressure sensor. The implement pressure sensor sends an electrical signal to the machine ECM. The sensor information is used to control engine speed and pump control. Also, an electrical signal from the machine ECM energizes the swing brake solenoid valve to release the swing parking brake.Note: The implement pressure sensor does not detect a boom lower or a swing operation.Low Pressure PWM Sensors
Illustration 5 g02263393Note: The values in Table 3 are for bench testing only. Values may not represent parameters for machine systems specifications.
Table 3
Operating pressure 10 MPa
Supply Voltage +7V ~ +14V
Output signal 500 100 Hz (PWM)
Output range 5% ~ 95% Negative Flow Control Pressure Sensors
The negative flow control (NFC) pressure sensors for the drive pump and idler pump are inputs to the machine ECM. The machine ECM uses this pressure information to determine the hydraulic demand requested by the operator. The machine ECM then sends a PWM driver to the NFC solenoids to control the pump flow rate.The NFC pressure sensors are located on the top on the main control valve in the end plate.For more information on the NFC pressure sensors, refer to Systems Operation, "Negative Flow Control System".High Pressure Sensors
Illustration 6 g02263513Note: The values in Table 4 are for bench testing only. Values may not represent parameters for machine systems specifications.
Table 4
Operating Pressure 50 MPa
Supply Voltage +7V ~ +14V
Output Signal 500 100 Hz (PWM)
Output Range 5% ~ 95% Drive Pump Pressure Sensor and Idler Pump Pressure Sensor
The drive pump pressure sensor and idler pump pressure sensors are inputs to the machine ECM. The drive pump and idler pump pressure sensors are located on the main control valve. The drive pump pressure sensor monitors the pressure of the drive pump oil in the front half of the main control valve high-pressure passages. The idler pump pressure sensor monitors the idler pump oil pressure in the rear half of the main control valve high-pressure passages.The pressure sensors send a pulse width modulated (PWM) input to the machine ECM. This pressure information is used for pump control and travel speed.Outputs
The ECM responds to decisions by sending electrical signals to the outputs. The outputs can create an action or the outputs can provide information to the operator or the service technician.On/Off Solenoids
Illustration 7 g01158530Note: The values in Table 5 are for bench testing only. Values may not represent parameters for machine systems specifications.
Table 5
Rated Voltage 24 VDC
Coil Resistance 41.5 2.1Ω (T=20° C) Hydraulic Lock Solenoid
The hydraulic lock solenoid is an output of the Machine ECM. The hydraulic lock solenoid is energized in order to enable the primary hydraulic pressure. The hydraulic lock solenoid is de-energized in order to disable the primary hydraulic pressure.This solenoid is activated while the key switch is in the ON position and