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| Illustration 1 | g03702004 |
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Diagram of the Machine Control Electronic Communication System (1) Machine ECM (2) Implement ECM (3) Travel pedal (4) Engine ECM (5) CAN A data link (6) Machine monitor (7) Machine security system (8) CAN B data link (9) Operator control panel (10) Product link (11) Service connector (12) Communication Adapter III (13) Electronic Technician (ET) | |
The following will cover information that pertains primarily with the pilot system and components that are controlled by the Machine ECM and the attachment Implement ECM.
When using this manual for the troubleshooting of the electrical system circuits, the complete electrical system schematic for your machine should also be used. Quick reference electrical connection diagrams are included throughout this manual. However, these diagrams do not show the machine wiring harness connections that are part of the circuit. The complete electrical system schematic illustrate all machine wiring harness connectors and the locations on the machine.
Electronic Control Module (ECM)
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| Illustration 2 | g03701860 |
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Electronic control modules are located to left rear side of the machine (1) Machine ECM (2) Implement ECM | |
The machine ECM is the control module that will use the programmed control logic to manage the operation of most of the machine functions. The machine ECM will use the data from the various input devices to determine the appropriate output response to operator commands.
The machine ECM determines all of the appropriate output commands and communicates this information to the Implement ECM on the SAE J1939 (CAN) data link.
The machine ECM will activate outputs in order to energize or de-energize solenoids that will control the installed machine functions.
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| Illustration 3 | g03701879 |
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Machine ECM Connectors (1) J1 connector (2) J2 connector | |
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| Illustration 4 | g03701995 |
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Machine ECM connector (70-pin) | |
| Machine ECM - J1 Contact Connections | ||
|---|---|---|
| Pin Location | Function | Description |
| 44 | 8 VDC sensor supply | Sensor power output |
| 45 | 8 VDC sensor return | Sensor power return (ECM ground) |
| Machine ECM - J2 Contact Connections | ||
|---|---|---|
| Pin Location | Function | Description |
| 33 | Boom pilot pressure sensor A | PWM input |
| 34 | Boom pilot pressure sensor B | PWM input |
| 48 | Boom head end pressure sensor | PWM input |
| 49 | VA boom pilot pressure sensor A | PWM input or Analog input |
| 50 | VA boom pilot pressure sensor B | PWM input or Analog input |
| 67 | CAN + | CAN Data Link (+) |
| 68 | CAN - | CAN Data Link (-) |
Pin Locations for Implement ECM
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| Illustration 5 | g03701995 |
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Machine ECM connector (70-pin) | |
| Implement ECM - Contact Connections | ||
|---|---|---|
| Pin Location | Function | Description |
| 13 | Boom Float solenoid | Solenoid driver |
| 17 | Boom down pilot pressure switch return | Driver return |
| 28 | Boom cylinder rod end pressure sensor | PWM input |
| 38 | Boom down pilot pressure sensor | Analog input |
| 42 | Boom float down solenoid | Sourcing driver output |
| 43 | Boom float down solenoid return | Sinking driver output |
| 55 | 8V sensor return | Sensor return |
| 68 | 8V sensor supply | 8V supply |
The inputs describe the status of the machine systems. Two types of inputs exist. The inputs can be either a switch type or a sensor type. Switches provide an open, a ground, or a + battery signal to the inputs of the controller. Sensors (frequency, PWM, or voltage) provide a changing signal to the sensor inputs of the controller.
Most sensor input circuits have an internal ECM "pull up voltage" that is present at the ECM contacts. An above normal voltage is internally connected to the ECM input circuit through a resistor. During normal operation, the sensor signal will hold the circuit at a certain signal amplitude. However, conditions such as a loss of power to a component, a disconnection, or an open circuit allow the circuit to be pulled high. The circuit is pulled high by the ECM pull up voltage. This situation will result in an above normal voltage condition at the ECM contact. As a result, the ECM will activate an FMI 03 (voltage above normal) diagnostic code for the affected circuit.
The types of ECM input sensor circuits that have pull up voltage present are:
- Pulse Width Modulated (PWM) sensor input circuits
- Active analog (voltage) input signal circuits
- Passive analog (resistance) input signal circuits
Pulse Width Modulated (PWM) Position Sensor Operation
When powered up, the position sensors continuously send a Pulse Width Modulated (PWM) square wave signal to the ECM. Any movement on a specific axis is detected by the position sensor for that axis. The duty cycle of the PWM sensor signal changes depending on the direction and amount of movement on the axis. The duty cycle is the percentage of time that the signal is high verses the amount of time the signal is low for one cycle. The more time that the duty cycle is high, the greater the percentage of the duty cycle will be.
The percentage of duty cycle signal for a typical position sensor will be recognized as valid is 10 ± 5 to 90 ± 5 percent. These percentages occur the extreme ends of the axis movement. A typical joystick thumbwheel that is in the center or neutral position would result in a duty cycle signal of approximately 50 ± 5 percent. For a foot pedal that is not depressed, a typical duty cycle signal would be 10 ± 5 percent. The duty cycle would be 90 ± 5 percent when the pedal is depressed.
The position sensors are calibrated by the ECM to relate a specific duty cycle signal to a specific axis position for the device being monitored.
The ECM will convert the duty cycle from the position sensor to a calibrated duty cycle signal. The ECM uses this signal and a software "map" to determine the appropriate output signal that will be applied to an output device.
Note: None of the PWM sensors require manual calibration. The machine ECM will perform an automatic calibration procedure at ECM power up.
The Boom system contains the following sensors:
- Boom pilot pressure sensor A
- Boom pilot pressure sensor B
- Boom head end pressure sensor
- VA boom pilot pressure sensor A
- VA boom pilot pressure sensor B
- Boom cylinder rod end pressure sensor
- Boom down pilot pressure sensor
The ECM responds to inputs by sending electrical signals to the outputs. The outputs can create an action or the outputs can provide information to the operator or service technician.
For control of on/off type solenoids and relays, the ECM will either turn ON or turn OFF the output for a component. The output command is based on the signals from the input devices that are involved in the system. The ECM will not vary the amplitude of the output, the circuit is either energized (on) or the circuit is de-energized (off). When the on/off output circuit is energized, most often system power will be used to energize the circuit and the output component.
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| Illustration 6 | g01158530 |
Note: The values in Table 4 are for bench testing only. Values may not represent parameters for machine systems specifications.
| Rated Voltage | 24 VDC |
| Coil Resistance | 32.0 ± 3.2Ω (T=20° C) |
The Boom system contains the following on/off solenoids:
- Boom float down solenoid
- Travel pilot pressure solenoid
- Transmission gear shift 1 and gear shift 2
- Travel direction
Proportional Reducing Solenoid Valve
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| Illustration 7 | g02703776 |
Note: The values in Table 5 are for bench testing only. Values may not represent parameters for machine systems specifications.
| Current Range | 0 mA ~ 700 mA |
| Coil Resistance | 11.5 ± 0.5Ω (T=20° C) |
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| Illustration 8 | g03787696 |
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Soft switch panel (1) Smart boom control button | |