Sensors are used in order to monitor engine operation. Wiring harnesses connect the sensors to the control modules. The modules use information from the sensors for monitoring and controlling the engine. If an abnormal occurrence is detected, the information is also used to generate warnings, shutdowns, and diagnostic codes.
Junction Box
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| Illustration 1 | g00820755 |
Inside of a typical junction box (1) Terminal strip (2) Wiring to the emergency stop button on the door (3) Electronic service tool connector (4) Circuit breaker | |
The junction box contains terminal strips (1) for connections from the engine harness. Wiring (2) is for the emergency stop switch on the outside of the door for the junction box. Connector (3) is for use with an electronic service tool. Circuit breaker (4) helps protect the electrical system from power surges.
Two basic electrical systems are available to provide engine protection: energize-to-run and energize-to-shutoff. Protection from low oil pressure, high coolant temperature, and engine overspeed is provided. Both systems are capable of activating a gas shutoff valve and grounding the ignition system. An external power source of 24 volts is required for these systems.
EIS Control Module
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| Illustration 2 | g00824410 |
EIS control module | |
The EIS control module activates warnings and shutdowns for the following types of conditions:
- Electrical system malfunctions
- Excessive detonation
- Incorrect programming
The electronic ignition system is self-diagnostic. If a problem with the system is detected, the EIS control module can activate a warning or a shutdown. If this occurs, a diagnostic code is issued in order to inform the operator of the specific problem.
For a complete list of the warnings, shutdowns, and corresponding diagnostic codes, refer to Electronic Troubleshooting, SENR6535, "G3408C & G3412C Engines".
Remote Control Panel (Status)
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| Illustration 3 | g00785285 |
Remote Control Panel (Status) (1) "WARNING" indicator (2) "SHUTDOWN" indicator (3) "POWER ON" indicator (4) "DIAGNOSTIC RESET" switch (5) Status control module (6) Engine control switch (7) "EMERGENCY STOP" button | |
The yellow "WARNING" indicator (1) flashes or stays lighted in order to indicate the occurrence of an abnormal operating condition. A warning is not severe enough to cause a shutdown. However, this signifies a serious problem. If a warning occurs, a diagnostic code for the condition is logged in the engine control module. Correct the cause of the warnings as soon as possible in order to avoid problems with operation.
The red "SHUTDOWN" indicator (2) illuminates continuously when an adverse operating condition causes a shutdown. A diagnostic code for the condition is logged in the EIS control module. If the engine is shut down due to parameters that are out of acceptable limits, the red indicators on status control module (5) will also illuminate.
"POWER ON" indicator (3) illuminates continuously when power is supplied to the control panel.
"DIAGNOSTIC RESET" switch (4) is a toggle switch that is used to clear diagnostic codes from the engine control module. The switch cannot clear individual codes. Use of the switch will clear all codes that are active in the engine control module. Do not clear the codes until the problems that caused the codes are addressed.
Status control module (5) has several engine monitoring and control functions.
Engine control switch (6) is used to control starting the engine and stopping the engine.
"EMERGENCY STOP" button (7) is used to stop the engine in an emergency situation. When the button is pressed, the status control module shuts off the fuel via the gas shutoff valve. The module also grounds the ignition system. The "EMERGENCY STOP" button must be reset before the engine will start.
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| Illustration 4 | g00785287 |
(1) Liquid crystal display (LCD) (2) Switch (3) "OVERCRANK" indicator (4) "LOW OIL PRESSURE" indicator (5) "OVERSPEED" indicator (6) "EMERGENCY STOP" indicator (7) "HIGH COOLANT TEMPERATURE" indicator (8) "AUXILIARY SHUTDOWN" indicator | |
Liquid Crystal Display (LCD) - Symbols for the following parameters are located under LCD (1). The LCD provides a digital display of the status of these parameters. When the status of a parameter is displayed, an arrow at the bottom of the LCD points the corresponding symbol. The display can be in metric units or English units.
| Hour meter - When the arrow points to this symbol, the hours of engine operation are displayed. |
| Engine speed - When the arrow points to this symbol, the engine rpm is displayed. |
| System battery voltage - When the arrow points to this symbol, the voltage of the electrical system's battery is displayed. |
| Engine oil pressure - When the arrow points to this symbol, the engine oil pressure is displayed. |
| Coolant temperature - When the arrow points to this symbol, the Coolant temperature is displayed. |
The parameters are displayed sequentially. To lock the display onto one of the parameters, press switch (2). To resume the sequential display, press the switch again.
The LCD is also used to display diagnostic codes. A diagnostic code indicates that the system has detected a problem with a component that is associated with the status control module. When a diagnostic code is displayed, the arrow that indicates the display of the parameters will be missing. A flashing "dIAG" will be displayed. If more than one diagnostic code is present, the diagnostic codes will be displayed in sequence.
To clear the diagnostic codes from the LCD, turn the engine control switch to the "Stop" position. For information on diagnostic codes, refer to these publications:
- Systems Operation/Testing and Adjusting, SENR6420, "Control Panel (Status-Timing)"
- Electronic Troubleshooting, SENR6535, "G3408C & G3412C Engines".
The status control module has six indicators (Illustration 4) that indicate engine shutdowns. The shutdowns that are associated with the indicators are described below.
| "OVERCRANK" - If the engine fails to start within a programmed amount of time or if the number of crank cycles are exceeded, the status control module will deactivate the starting sequence. Indicator (3) will flash. The engine control switch must be turned to the "Stop" position before another attempt to start the engine can be made. |
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| "LOW OIL PRESSURE" - There are two setpoints for low engine oil pressure. The setpoints depend on the engine rpm. One setpoint is for engine rpm that is below the oil step speed setting. The other setpoint is for engine rpm that is above the oil step speed setting. If the engine oil pressure decreases below the setpoint, the fuel to the engine will be shut off. Indicator (4) will flash. |
| "OVERSPEED" - If the engine rpm exceeds the setpoint for overspeed, the fuel and the ignition will be shut off. Indicator (5) will flash. |
Note: A verify button for overspeed is located on the back of the status control module. This enables a test of the overspeed protection system to be performed. Refer to Systems Operation/Testing and Adjusting, SENR6420, "Control Panel (Status-Timing)" for information on the service procedure.
| "EMERGENCY STOP" - Indicator (6) will flash if the "EMERGENCY STOP" button is used to stop the engine. |
Note: Do not use the coolant temperature sensor to monitor the operation of jacket water heaters (if equipped).
| "HIGH COOLANT TEMPERATURE" - If the coolant temperature exceeds the setpoint, the fuel will be shut off. Indicator (7) will flash. |
"AUXILIARY SHUTDOWN" indicator (8) indicates that an external request was used to stop the engine. If the auxiliary shutdown is not used, the "AUXILIARY SHUTDOWN" indicator can be used as a spare indicator.
Note: Only the indicators on the status control module are reset when the engine control switch is turned to the "Stop" position. Diagnostic codes must be cleared with the "DIAGNOSTIC RESET" switch.
EMCP II
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| Illustration 5 | g01415965 |
Control panel (EMCP II) | |
Refer to Service Manual, SENR5394, "Electronic Modular Control Panel II (EMCP II) for Gas Engines" for more information on the EMCP II.