308C Excavator Electrical and Electronic System – Monitoring System



Illustration 1 g00844863

Inputs and Outputs for the Monitoring System

(1) Fuel level gauge

(2) Engine coolant temperature gauge

(3) Hydraulic oil temperature gauge

(4) Low fuel level indicator

(5) Indicator for battery charge

(6) Indicator for engine coolant temperature

(7) Indicator for low engine oil pressure

(8) Low idle indicator

(9) Glow indicator

(10) Fuel level sensor

(11) Engine coolant temperature sensor

(12) Hydraulic oil temperature sensor

(13) Engine oil pressure switch

(14) Alternator

(15) Key start switch

(16) Controller

(17) Switch for one touch low idle

(18) Monitor panel

The monitoring system continuously watches machine systems. Information about the machine condition is displayed on monitor panel (18). A fault alarm in the monitor panel can indicate a problem with the machine. The following systems are representative of the machine systems that are monitored: engine coolant temperature, hydraulic oil temperature and fuel level. The following indicators are used to monitor the machine systems:

  • Fuel level gauge (1)

  • Engine coolant temperature gauge (2)

  • Hydraulic oil temperature gauge (3)

  • Low fuel level indicator (4)

  • Indicator for battery charge (5)

  • Indicator for engine coolant temperature (6)

  • Indicator for low engine oil pressure (7)

  • Low idle indicator (8)

  • Glow indicator (9)

Except for the action alarm, the gauges and indicators are located on monitor panel (18). The action alarm is located in the console.

Description of Gauges and Indicators

Power On Test

To ensure proper operation of the monitoring system, the action alarm and indicators are tested whenever the monitor is powered up. When key start switch (15) is turned to the ON position, all of the indicators on monitor panel (18) will turn ON for approximately 2.5 seconds, and the action alarm will sound for approximately 2.5 seconds.

Fuel Level Gauge

Fuel level gauge (1) receives an input signal from fuel level sensor (10). This gauge indicates the amount of fuel in the fuel tank.

Engine Coolant Temperature Gauge

Engine coolant temperature gauge (2) receives an input signal from engine coolant temperature sensor (11). This gauge indicates the engine coolant temperature. The red range will illuminate when the engine coolant temperature reaches 105 °C (221 °F).

Hydraulic Oil Temperature Gauge

Hydraulic oil temperature gauge (3) receives an input signal from hydraulic oil temperature sensor (12). This gauge indicates the hydraulic oil temperature. The red range will illuminate when the hydraulic oil temperature reaches 98 °C (208 °F).

Low Fuel Level Indicator

Low fuel level indicator (4) will illuminate when the fuel level is below a set value.

Indicator for Battery Charge

The indicator for battery charge (5) monitors the charging frequency of alternator (14). When the system voltage is below a set value, the indicator for battery charge (5) will illuminate.

Indicator for Engine Coolant Temperature

The indicator for engine coolant temperature (6) receives an input signal from engine coolant temperature sensor (11). When the engine coolant temperature reaches 105 °C (221 °F), the indicator for engine coolant temperature (6) will illuminate.

Indicator for Low Engine Oil Pressure

The indicator for low engine oil pressure (7) receives the input signal from engine oil pressure switch (13). The indicator for low engine oil pressure (7) will illuminate and the action alarm will sound when the engine oil pressure is below a set value.

Low Idle Indicator

When the switch for one touch low idle (17) is depressed to activate the low idle system, low idle indicator (8) illuminates.

Glow Indicator

While key start switch (15) is in the PREHEAT position, glow indicator (9) illuminates.