The analog sensors that are used consist of the following sensors:
- Coolant Temperature
- Turbocharger Outlet Pressure
- Turbocharger Inlet Pressure
- Atmospheric Pressure
- Oil Pressure (In And Out Of Filters)
- Fuel Pressure (In And Out Of Filters)
- Crankcase Pressure
- Aftercooler Temperature
Atmospheric Pressure Sensor - This sensor measures barometric pressure. The sensor sends the signal to the electronic control module (ECM) for use in engine control and in operation.
Before Top Center (BTC) - BTC is the 180 degrees of crankshaft rotation before the piston reaches Top Center in the normal direction of rotation.
Calibration - Calibration is an electronic adjustment of a sensor signal.
CAT Data Link - The data link is an electrical connection for communication with other onboard microprocessor based devices that use the data link. The data link is also the medium for communication that is used for programming and troubleshooting with the electronic service tool.
Coolant Temperature Sensor - This sensor measures the temperature of the jacket water coolant. The sensor sends the signal to the ECM. The engine's coolant temperature is used in cold mode operation. Coolant temperature is used to provide engine protection. Coolant temperature is also used in order to optimize performance.
Crankcase Pressure Sensor - This sensor measures the crankcase pressure. The sensor sends the signal to the ECM. The information is used to warn the operator of high crankcase pressure.
Desired RPM - The desired RPM is input to the electronic governor within the ECM. The electronic governor uses the engine speed inputs from the Speed/Timing Sensor in order to determine the desired RPM.
Diagnostic Code - A diagnostic code is an indication of a problem or event in the EUI system.
Digital Sensors - The exhaust temperature sensor and all the digital sensors that are used on the EUI system are powered from a 8.0 ± 0.5 VDC supply. The timing sensor within the ECM is powered from a 12.5 ± 1.0 VDC supply. Digital sensors produce a Pulse Width Modulation or a Duty Cycle signal. The digital sensors that are used are the Exhaust Temperature Sensor and the Speed/Timing Sensor.
Direct Current (DC) - Direct current is the type of current that flows consistently in only one direction.
Duty Cycle - See Pulse Width Modulation.
Electronic Control Analyzer And Programmer (ECAP) - ECAP is a Caterpillar electronic service tool. ECAP is used for programming and diagnosing various electronic controls.
Electronic Control Module (ECM) - The ECM is the engine's control computer. The ECM provides power to the electronics for the EUI. The ECM monitors data that is input from the EUI. The ECM acts as a governor in order to control engine rpm.
Electronic Engine Control - The electronic engine control is a complete electronic system. The electronic engine control monitors the engine operation under all conditions. The electronic engine control also controls the engine operation under all conditions.
Electronic Technician (ET) - ET is a Caterpillar electronic service tool that is used for diagnosing and programming a variety of electronic controls.
Electronic Unit Injector (EUI) - The injection pump is a mechanically actuated, electronically controlled unit injector. The EUI combines the pumping, electronic fuel metering, and injecting elements into a single unit.
Exhaust Temperature Sensor - These sensors measure the exhaust temperature to the turbochargers. The sensor sends a signal to the ECM. The exhaust temperature is used in order to derate the engine. This is done in order to prevent further engine damage if a unacceptable temperature is reached due to some engine failure. The ECM will send a signal to the engine monitoring system in order to warn the operator of the problem.
Filtered Oil Pressure Sensor - This sensor measures the engine's oil pressure out of the filters. The sensor sends the signal to the ECM. The ECM provides the monitoring of oil pressure and operator warning through the engine's monitoring system with the oil pressure sensor.
Flash - This is a method of transferring software over the data link with an electronic service tool.
Fuel Position - The fuel position is a signal within the ECM. The signal is from the electronic governor. The signal goes to the fuel injection control. The signal is based on the desired engine speed, the rated position, and engine speed.
Harness - The harness is the bundle of wiring that connects all the components of the EUI system.
Injection Timing Control - Injection timing control is the use of the electronic unit injectors in order to provide total electronic control of the fuel injection timing.
Liquid Crystal Display (LCD) - The LCD is a part of the monitoring panel. The monitoring panel is used to display information to the operator about the condition of the engine systems and system diagnostic information.
Open Circuit - An open circuit is a broken electrical wire connection. The signal or the supply voltage cannot reach the intended destination.
Parameter - A parameter is a programmable value which affects the characteristics or the behavior of the engine.
Password - A password is a group of numeric characters or alphanumeric characters. A password is designed to restrict the changing of information in the ECM. The EUI system requires correct factory passwords in order to clear certain logged events. Factory passwords are also required in order to change the FLS configuration parameters.
Personality Module - A personality module refers to the software that is downloaded onto the small, blue module. The module is inserted into the ECM. The module contains all the instructions (software) for the ECM and performance maps for a specific application.
Pulse Width Modulation (PWM) - A PWM is a digital type of electronic signal that corresponds to a measured variable. The length of the pulse (signal) is controlled by the measured variable. The variable is quantified by a certain ratio. This ratio is the percent of "on-time" that is divided by the percent of "off-time". A PWM signal is generated by the Speed/Timing Sensor.
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| Illustration 1 | g00284479 |
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Example Of Pulse Width Modulation | |
Rated Fuel Limit - The rated fuel limit indicates the maximum allowable fuel position. The rated fuel limit will produce rated power for this engine configuration.
Reference Voltage - The reference voltage is a regulated voltage that is used by the sensor in order to generate a signal voltage.
Sensor - A sensor is used to detect a change in the pressure, in the temperature, or in mechanical movement. When any of these changes are detected, a sensor converts the change into an electrical signal.
"Serv Code" Indicator - This indicator is used to warn the operator of the presence of active diagnostics.
Short Circuit - A short circuit is an electrical circuit that is mistakenly connected to an undesirable point. For example, an electrical contact is made with the frame whenever an exposed wire rubs against a machine's frame.
Signal - A signal is a voltage or a wave that is used to transmit information that is typically from a sensor to the ECM.
Speed/Timing Sensor - This sensor provides a Pulse Width Modulated signal to the ECM. The ECM interprets this signal as the crankshaft position and the engine speed.
Static Timing - Static timing is the basis for fuel injection timing and valve mechanism operation. Static timing is determined by the Timing Reference Ring and the alignment of the rear gear group and the camshaft timing pin.
Subsystem - A subsystem is a part of the EUI system that relates to a particular function.
Supply Voltage - Supply voltage is a constant voltage that is supplied to a component in order to provide electrical power for operation. Supply voltage may be generated by the ECM. Supply voltage may also be the battery voltage that is supplied by the engine wiring.
"T" Harness - This harness is a test harness that is designed to permit normal circuit operation and the measurement of the voltage simultaneously. Typically, the harness is inserted between the two ends of a connector.
Total Tattletale - The total tattletale is the total number of changes to all system parameters.
Turbocharger Inlet Pressure Sensor - This sensor measures the inlet air pressure in the tubes in the air induction system. The sensor sends signals to the ECM.
Turbocharger Outlet Pressure Sensor - This sensor measures the inlet manifold air pressure. The sensor sends a signal to the ECM.