Hyundai Yanmar TNV Series Manual page 27

CONTROL SYSTEM
The following describes each of the components shown in Figure 2-4.
[Main relay]
• Allows avoiding a long electrical wiring between the battery and E-ECU terminal VB.
• Allows self-holding of the E-ECU power and logging of engine events including faults and running time
when the key switch is off.
• Prevents reverse current from being applied to the E-ECU or rack actuator in case of reverse connection
of battery terminals.
[Rack actuator relay]
• Cuts off the power to the actuator to stop the engine when the key switch is turned off, regardless whether
or not the main relay causes self-holding of the E-ECU power.
• Cuts off the power to the actuator to stop the engine when the sub microcomputer detects overspeed,
regardless of the status of the main microcomputer.
[Sub relay]
• Prevents the capacity of the main relay circuit from exceeding 7.0 A. (The design capacity of the fuse in
the main relay circuit must be 10 A or less because the nominal cross sectional area of the cable
applicable to the rack actuator connector is 0.75 mm
• Prevents reverse current from being applied to the I/O terminals of the E-ECU panel in case of reverse
connection of battery terminals.
[Air heater relay]
• Enables the E-ECU to provide ON-glow control, simultaneous energization or after heating to the starting
aid (air heater or glow plug).
[Starter relay]
• Prevents the starter motor from starting until the rack self-diagnostics on power-on is completed (for
approx. 0.5 second).
• Prevents failure caused by starter overrun.
• Limits the starter-on time to prevent failure caused by starter overcranking (optional feature).
• Synchronizes the starter operation with the crutch pedal switch position or the like (optional feature).
[Alternator terminal P]
• Provides backup rotation pulse signals to be used in cases where the rotation sensor fails to produce
engine rotation pulse output.
• Using backup rotation pulse signals degrades the accuracy of the engine speed measurements because
the signals do not reflect belt slip. The engine speed is therefore limited as long as the backup signals are
used.
[Failure lamp]
• Alerts the operator to a fault occurring in the Eco-governor system or a start of energization of the E-ECU.
[Service tool coupler]
• Enables getting control data from the E-ECU or making a detailed diagnostics of the Eco-governor
system.
• Enables maintenance of data, programs, parameters etc. in the E-ECU.
2-8
2
).
TNV Application Manual