PISTON 3668298 - Caterpillar

Marine Auxiliary Engines
The throttle signal to the engine's ECM is a pulse width modulated signal (PWM). The ECM displays the throttle position as a percentage between 0 and 100 percent. The remote PWM signal is provided by the customer. The duty cycle of the PWM signal must be between 5 percent and 95 percent for a valid signal. The frequency of the PWM signal must be a frequency between 150 Hz and 1000 Hz.A potentiometer that is mounted in the user interface panel can be used to send a signal to the customer's speed control in order to allow local speed control of the engine. The potentiometer is available on the engine control panel. The potentiometer can be retrofitted as an option for the user interface panel.Marine Propulsion Engines
The throttle signal to the ECM can be a PWM signal or a 4 to 20 mA current signal. The ECM converts the throttle signal into a usable throttle position. The ECM displays the throttle position as a percentage between 0 and 100 percent.A local speed control is located in an interface in the engine room. The local speed control must have a PWM output to the ECM.A remote speed control can be located in the pilot house (bridge). The remote speed control can use either a PWM signal or a 4 to 20 mA current signal. A configuration parameter for the ECM is used to select the type of signal.The duty cycle of the PWM signal must be between 5 percent and 95 percent for a valid signal. The frequency of the PWM signal must be a frequency between 150 Hz and 1000 Hz.The 4 to 20 mA current signal is provided by the customer. The current signal is isolated through a pair of isolation transformers that are mounted in the user interface panel.Marine propulsion engines have two modes of operation. Each mode has a set of three governor gain factors that can be adjusted.
The default mode is a variable speed control that is used for sailing from point-to-point.
A constant speed control can be selected by grounding an input to the engine's ECM. This mode is used with an electronic propulsion system when it is necessary for the engine to maintain a fixed rpm. A variable pitch propeller controls the thrust and the position of the vessel.The mode for constant speed is selected when the ECM input for the "Engine Governor Constant Speed Mode Switch" is grounded.Some parameters must be programmed in order for the mode for constant speed to operate. A desired constant engine rpm must be determined.
The "Engine Governor Desired Constant Speed" is programmed with the desired rpm. The default is the engine's rated rpm.The factors for the governor gain are programmed at the factory in order to provide good performance. However, these factors are validated during the commissioning procedure. The factors are adjusted, if necessary.
The Governor Gain Factor 2 ("Prop Gain 2")
The Governor Minimum Stability Factor 2 ("Prop Int Min 2")
The Governor Maximum Stability Factor 2