The Marine Monitoring System consists of an off engine mounted Marine Engine Control Panel and the engine mounted sensors and associated wiring.
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Marine Engine Control Panel
The Marine Engine Control Panel contains the following components:
- A personal computer (PC) that displays the operating information
- A minimum protection backup relay system
- Control switches for starting the engine
- Control switches for stopping the engine
- The engine speed switch
- A Programmable Logic Controller
Personal Computer
The PC display provides the engine status for the operator.
Control Switches
The following controls are located on the Marine Engine Control Panel:
- "EMERGENCY STOP" button
- "OFF/RESET-LOCAL-REMOTE" switch
- "PRELUBE-RUN-START" switch
- "FUEL CONTROL" switch
- "HORN SILENCE-LAMP TEST" switch
The control switch on the Marine Engine Control Panel permits local control of the engine or remote control of the engine. This switch can also be placed in the OFF/RESET position.
The "FUEL CONTROL" switch can be placed in the OFF position or the ON position.
Weight of the Marine Monitoring System
Each of the following part numbers have a combined weight of 90 kg (198 lb):
- 146-5522 EMCP Electronic Control
- 146-5523 EMCP Electronic Control
- 146-5524 EMCP Electronic Control
- 146-5525 EMCP Electronic Control
The 147-5676 Instrument Panel Mounting has a weight of 86 kg (190 lb).
Programmable Logic Controller
The programmable logic controller provides complete monitoring and control for a Caterpillar 3600 Engine. The basic modular programmable logic controller consists of the following components:
- Power Supply
- Central Processing Unit Module (CPU)
- Chassis
- Input Modules
- Output Modules
- Engine Speed Switch
The programmable logic controller is the computer that conducts the following engine functions:
- Control
- Monitor
- Protection
The CPU in the programmable logic controller contains the software that controls programmable logic controller behavior.
The following components are used as engine sensors: contactors, thermocouples, resistance temperature detectors (RTDS) and transducers.
Power Supply
The power supply delivers 24 VDC for the following components: the CPU, the chassis, the control panel, the input modules and the output modules. The 24 VDC is typically provided by a battery set.
Central Processing Unit Module
The operator can configure the memory. The operator can configure the memory for data. The operator can also configure the memory for the storage of programs. The memory size is adjustable from 1K to 64K. The CPU is supported by a variety of modules. These modules include digital modules, analog modules, and smart modules. The CPU is seated in slot 0 of the programmable logic controller chassis.
Discrete Input Modules
The discrete input modules are in the following list:
- Thermocouple Module
- RTD Input Module
- Digital Modules
- Analog Modules
When you apply a voltage to the channel, the relay is energized. An energized input closes all of the contacts that are normally open. An energized input will open all of the contacts that are normally closed. Digital modules are used to determine whether a circuit is ON/OFF. A number of modules are available. The MMS modules have sixteen channels.
Discrete Output Modules
The programmable logic controller discrete output modules consist of analog modules and digital modules. Voltage control is provided by the output modules. A module provides power for the following list of functions: energizing the lamps, energizing the relays, energizing the fuel shutoff solenoid and energizing the air shutoff solenoid.
Engine Speed Switch
The speed switch accepts a signal from the magnetic pickup. The magnetic pickup is mounted on the engine. The speed switch determines the engine speed from the signal. The speed switch provides contacts for the following list of conditions:
- Crank Terminate
- Engine Oil Step Pressure
- Engine Overspeed
- Nine Second Time Delay
Engine Mounted Sensors
Engine mounted sensors provide the programmable logic controller with engine operating information. The programmable logic controller uses the following four types of engine sensors:
- Contactor
- Resistance Temperature Detector (RTD)
- Thermocouple
- Transducer
Contactor
A contactor is a pressure switch or a contactor is a level switch. Contactors can be adjusted in order to operate at a given pressure or temperature.
Resistance Temperature Detector
A Resistance Temperature Detector (RTD) measures the change in electrical resistance as a function of temperature. As the temperature increases the resistance increases. As the temperature decreases the resistance decreases. The resistance of a RTD varies linearly with temperature.
The signal is routed from the engine mounted junction box to terminals in the Marine Engine Control Panel. The programmable logic controller routes the signal to a RTD module. The RTD module converts the signal into the parameter.
Thermocouple
A thermocouple is a temperature sensor. The thermocouple consists of two different metals. The metals are joined together at one end. A small voltage is produced when the junction is heated. The change in voltage is interpreted by an electronic device in order to determine a change in temperature.
Caterpillar uses K type thermocouples. The K type thermocouples have ranges from -200 °C (-328 °F)to 1260 °C (2300 °F). This temperature range corresponds to a voltage range of negative 5.9 mV to 51.0 mV.
Transducer
A transducer converts various engine parameters into an electrical signal. Transducers monitor the following list of parameters :
- Pressure
- Temperature
- Frequency
- Voltage
- Power
A transducer's signal is linearly proportional to the value of the parameters. Most transducers have an electrical signal between 4 mA and 20 mA.
The signal is routed from the engine mounted junction box to terminals in the Marine Engine Control Panel. The programmable logic controller routes the signal to an input module. The input module converts the signal into the parameter.