Closed - The switch connects the control input to frame ground.
Open - The switch connects the control input to nothing. (The input is floating.)
During normal operation, switches are in the normal position which could be normally open or normally closed depending on the switch used. When a condition exceeds the trip point of the switch, the switch will change from normal position (to open for a normally closed switch or to closed from a normally open switch). This tells the main display module of the abnormal condition. The main display module then begins the warning operation and the module notifies the operator of the abnormal condition (problem).
Note: For specifications on the switches, see the Electrical System Schematic for that particular machine.
Switch (Operator Mode Selector)
Grounding the operator mode selector switch causes the main display module to scroll through the available operator modes for the machine. Opening the selector switch places the Caterpillar Monitoring System in the currently displayed operator mode. A list of possible operator modes is shown at the beginning of the Modes of Operation section. See the Operation And Maintenance Manual in order to determine the "Operator Modes" that are available for the machine that is being serviced.
Level Switch (Hydraulic Oil)
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| Illustration 1 | g00304429 |
Level Switch (Hydraulic Oil) (1) Switch. (2) Schematic symbol. | |
During normal operation, level switch (1) is closed to ground. The switch opens when the liquid level is less than the minimum level. The open switch tells the main display module of the low level. The switch is open with the float in the DOWN position when the switch is off the machine.
Switch (Hydraulic Oil Filter)
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| Illustration 2 | g00935250 |
Switch (Hydraulic Oil Filter) (1) Switch. (2) Schematic symbol. | |
During normal operation, switch (1) is open. The switch closes to ground when the pressure for the hydraulic oil filter is greater than the specified value for the switch. The closed switch tells the main display module that the hydraulic oil filter is restricted. The switch is open when the switch is off the machine.
Pressure Switch (Left and Right Track Take Up)
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| Illustration 3 | g00304430 |
Pressure Switch (1) Switch. (2) Schematic symbol. | |
During normal operation, switch (1) is closed to ground. The switch opens when the pressure in the charge system is less than a specified pressure. The open switch tells the main display module that the charge pressure is too low. The connector contacts "A" and "C" are closed, and connector contacts "A" and "B" are open when the switch is off the machine.