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Sensors and Locations
SWITCHES
There are two on/off switch inputs to the electronic shutdown system for the starting and running of the system the start/restart and the engine start. These switches also have 470 ohm resistors in series in the lines. The start/restart switch powers up the electronic shutdown system (but does not switch power directly). The engine start switch closes when the air driven starter is activated (it does not have to stay closed). Its purpose is to start the inhibit timer that prevents the oil pressure and coolant circulation sensors from shutting the engine for some 25 seconds after start. If this switch were not to close, the engine would start and run ignoring the oil pressure and coolant circulation sensors. The start fault LED comes on when the oil pressure becomes normal and the start engine switch has not been closed. In that condition, if there is an oil pressure loss while running, the engine will shutdown after the oil pressure is lost. The start fault display LED is an important indicator of possible trouble in the future.
SENSORS
The sensors are mechanical or electronic switches with 470 ohm resistor in series. If the switch is closed (and the resistance through the line is 470 ohm), the sensor is signalling normal condition. If the switch is open (and the resistance through the line is infinity), the sensor is signalling alarm, or the wire is broken. If the resistance through the line is closed to short circuit, the wire is damaged.
SENSOR LOCATIONS
Engine Coolant Level Sensor
The engine coolant level sensor is located in the engine make up tank adjacent to the engine. This sensor monitors the engine coolant level and will shut the machine down by stopping power to the solenoid valve. This valve will open exhausting air pressure from the system thus the fuel shutdown cylinder will close the fuel rack. This closes of fuel to the engine and shuts the engine down. There is no need for routine calibration of the coolant level sensor as long as routine testing is carried out daily.
Engine Coolant Level Sensor
Exhaust Gas Temperature Sensor
The exhaust gas temperature sensor is set to shut the engine when the temperature reaches 70°C. When the exhaust temperature rises to 70°C at the exhaust outlet the valve will open exhausting air pressure from the safety system, thus the fuel shutdown cylinder will close the fuel rack, this closes of fuel the supply and shuts the engine down. There is only one sensor located in the gas path at the end of the outlet pipe.
Exhaust Gas Temperature Sensors
Engine Coolant Temperature Sensor
The coolant temperature sensor is set at 105°C, the sensor monitors the engine coolant temperature.
When the engine coolant temperature rises above 105°C the sensor will stop power to the solenoid valve. This valve will open exhausting air pressure from the system thus the fuel shutdown cylinder will close the fuel rack. This closes of fuel to the engine and shuts the engine down.
Engine Coolant Temperature Sensor
Engine Oil Pressure Sensor Testing
The engine oil pressure sensor is located under the dash panel in the line to the engine oil pressure gauge. There is no need for routine calibration of the oil pressure sensor as long as the correct operation is verified at start up. A test valve is located in the operator’s compartment to verify the oil pressure sensor is operating correctly. This will shut the machine down by stopping power to the solenoid valve. This valve will open exhausting air pressure from the system thus the fuel shutdown cylinder will close the fuel rack. This stops the fuel to the engine and shuts the engine down
Engine Oil Pressure Sensor Engine Oil Pressure Test Button Valve
Low Hydraulic Oil Sensor
The low hydraulic oil level sensor is located on the inspection cover of the hydraulic tank, when the oil level drops below the prescribed level the machine will shutdown by stopping power to the solenoid valve. This valve will open exhausting air pressure from the system thus the fuel shutdown cylinder will close the fuel rack, this stops the fuel to the engine and shuts the engine down.
Low Hydraulic Oil Level Sensor
The Low Hydraulic Oil Sensor is connected into the same wiring loom as the Low Engine Coolant Level Sensor and thus is indicated with the same display LED on the display panel.
Low Exhaust Conditioner Water Sensors
There are two low water shutdown sensors fitted to the outside of the float chamber plate. If the conditioner water drops below the prescribed level this will shut the machine down by stopping power to the solenoid valve. This valve will open exhausting air pressure from the system thus the fuel shutdown cylinder will close the fuel rack. This stops the fuel to the engine and shuts it down.
Shutdown Sensors
Low Exhaust Conditioner Water Sensor
Filter Regulator Oil Pressure Shutdown Test Valve Safe Start Valve Brake Interlock Pilot Valve
Oil Pressure Shutdown Sensor Transmission Declutch Pilot Valve Start Initiate Start/Park Brake Interlock Run Solenoid Reset Valve
