COVER AS 2176732 - Caterpillar

Illustration 5 g02332474The values in Table 5 are for bench testing only. Values may not represent parameters for machine systems specifications.
Table 5
Activation Pressure 490 49 kPa (71 7 psi)
Deactivation Pressure 294 kPa (43 psi) MIN
Rating + 12V ~ +32V
0.01 Amp to 1 Amp
Pressure Range 0 to 10 MPa The pressure switches include:
Implement pressure switchImplement Pressure Switch
The implement pressure switch sends an input signal to the machine ECU. 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 switch. The increase of pilot pressure activates the implement pressure switch. The implement pressure switch sends an electrical signal to the machine ECU. The switch information is used to control engine speed and pump control. Also, an electrical signal from the machine ECU energizes the swing brake solenoid valve in order to release the swing parking brake.Note: The implement pressure switch does not detect a boom lower or a swing operation.Outputs
The ECU 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.Solenoids
On/Off Solenoids
Illustration 6 g01158530The values in Table 6 are for bench testing only. Values may not represent parameters for machine systems specifications.
Table 6
Rated Voltage 24 VDC
Coil Resistance 32.0 3.2Ω (T=20° C) The On/Off solenoids include:
Hydraulic lock solenoidHydraulic Lock Solenoid
The hydraulic lock solenoid is an output of the Machine ECU. 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 the hydraulic lock lever is in the UNLOCK position.Proportional Reducing Solenoid Valve
Illustration 7 g03462498The values in Table 7 are for bench testing only. Values may not represent parameters for machine systems specifications.
Table 7
Current Range 0 mA ~ 700 mA
Coil Resistance 11.5 0.5Ω (T=20° C)
Illustration 8 g03462556
A - Port pressure (kPa) vs Current (mA)
The P-Port is blocked and does not allow pressure to the A-port. Therefore, the machine ECU must apply current to the PRV in order to sent pressure to the A-port of the PRV.The PRV's include:
Negative Flow Control 1 Limit PRV
Negative Flow Control 2 Limit PRV
Power Shift Pressure PRVNegative Flow Control 1 Limit PRV and Negative Flow Control 2 Limit PRV
Two proportional reducing valves for negative flow control are used to control the amount of NFC signal to the pump regulators. The machine ECU receives various input signals to control the flow limitation from the main hydraulic pumps. When the NFC valves are energized by the machine ECU, pilot oil pressure is directed to the main hydraulic pump regulators from the pilot manifold. The pilot oil pressure causes the hydraulic pumps to destroke which reduces hydraulic oil flow.Power Shift Pressure PRV
The power shift pressure PRV is used to destroke the main pump under load to maintain