PINION-DRIVE 9S9774 - Caterpillar

System Operation Description:The customer's emergency stop switch sends a signal to the Electronic Control Module (ECM). The signal is sent to two terminals on the ECM. The signals are used to determine if the emergency stop switch is active. The emergency stop switch is active when the switch is in the open state and the two signals are held high. The emergency stop switch is inactive when the switch is in the closed state and the two signals are held low.If the ECM is powering up and one of the signals from the emergency stop switch is in a different state from the other signal, the ECM knows that one of the signals is faulty. If one of the signals from the emergency stop switch is in a different state from the other signal, the ECM will generate a diagnostic code that remains active until power to the ECM is cycled. The ECM will not allow the crank cycle to begin if the signals are opposite of each other. The ECM will allow the engine to be started manually in this state. The ECM monitors the emergency stop signals at all times. If the engine is running and one of the signals from the emergency stop switch changes states, the engine will continue to run. The ECM initiates an emergency stop shutdown only when both signals are in the open state during engine operation.When a signal from the emergency stop switch is received, the Generator Set Control (GSC+) will activate the air shutoff solenoid.For safety, the ECM will not allow the starting sequence to begin when the emergency stop switch is activated. The engine will not be able to restart until the following conditions are met:
The engine rpm must equal zero.
The emergency stop inputs must go low.
The ECM has been reset.Note: If one of the signals from the emergency stop switch is in a different state from the other signal, the screen for the Caterpillar Electronic Technician (ET) will display the warning "INVALID DATA".Note: The Generator Set has a jumper wire between terminals 6 and 9 on the Engine Control Switch (ECS). This jumper wire provides power to the GSC+ when the battery disconnect switch is closed and the ECS is in the OFF/RESET position. Unless a timer is installed in the circuit, this jumper wire also provides power to the key switch input of the engine ECM when the battery disconnect switch is closed and the ECS is in the OFF/RESET position. The timer interrupts power to the key switch input of the engine ECM when the battery disconnect switch is closed and the ECS is in the OFF/RESET position. Cycling power to the key switch input of the ECM will reset the ECM and all active diagnostic codes. The bottom dial on the timer should be set to 0.7. The middle dial on the timer should be set to 3 seconds. The top dial on the timer should be set to E.
Illustration 1 g00835826
Typical schematicTest Step 1.