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| Illustration 1 | g01180805 |
Speedometer/tachometer circuit | |
The components of the speedometer/tachometer circuit are the transmission output speed sensor #1, the transmission output speed sensor #2, the Power Train/Chassis Electronic Control Module (Power Train/Chassis ECM), the primary speed/timing sensor, the secondary speed/timing sensor, the Engine Electronic Control Module (Engine ECM), the speedometer/tachometer module and the Caterpillar Monitoring System.
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| Illustration 2 | g01180806 |
Front view of cab (front cover plate removed) (1) Power Train/Chassis ECM | |
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| Illustration 3 | g01037735 |
Left side view of engine (2) Engine ECM | |
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| Illustration 4 | g01180808 |
Dash panel (3) Caterpillar Monitoring System | |
With the battery disconnect switch in the ON position, 24 volt power is supplied from the batteries via circuit breaker #1 to the Power Train/Chassis ECM.
With the key start switch in the ON position, 24 volt power is supplied from the batteries via circuit breaker #13 to the Power Train/Chassis ECM, via circuit breaker #4 and circuit breaker #12 to the Engine ECM and via circuit breaker #11 to the Caterpillar Monitoring System.
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| Illustration 5 | g01037186 |
Right side view of transmission (4) Transmission output speed sensor #1 (5) Transmission output speed sensor #2 | |
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| Illustration 6 | g01038327 |
Left side view of engine (6) Primary speed timing sensor | |
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| Illustration 7 | g01038328 |
Left side view of engine (7) Secondary speed/timing sensor | |
Transmission output speed sensor #1 (4), transmission output speed sensor #2 (5), primary speed/timing sensor (6), and secondary speed/timing sensor (7) are magnetic pick-ups. An electrical pulse is generated whenever a gear tooth interrupts the magnetic field. This signal is then sent to the relative ECM.
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| Illustration 8 | g01037189 |
Dash panel (8) Speedometer/tachometer module | |
With the machine moving, the transmission output speed sensor #1 and transmission output speed sensor #2 generate a signal that is sent to Power Train/Chassis ECM (1). The machine ground speed is determined by the Power Train/Chassis ECM and sent to Caterpillar Monitoring System ECM (3) via the CAT Data Link. The Caterpillar Monitoring System ECM sends a signal to speedometer/tachometer module (8) to display the ground speed.
While the engine is running, primary speed/timing sensor (6) and secondary speed/timing sensor (7) generate a signal that is sent to Engine ECM (2). Engine ECM (2) determines the engine rpm. Engine ECM (2) sends the signal via the CAT Data Link to Caterpillar Monitoring System (3). Caterpillar Monitoring System (3) sends a signal to speedometer/tachometer module (8) to display the engine speed.