Komatsu 730E Operation & Maintenance Manual page 152

Payload Meter III - Section 60
Page 60-8
Key Switch Input
PLM III monitors the status of the key switch. 24VDC
indicates that the key switch is ON. Open indicates
the key switch is OFF. The payload meter does not
receive its electrical power from the key switch cir-
cuit. The payload meter will remain on for several
seconds after the key switch is removed. When the
key switch power is removed, payload meter per-
forms a series of internal memory operations before
turning itself off. To allow for these operations, the
key switch must be turned off for at least 15 seconds
before turning the key switch back ON. The payload
meter will automatically reset itself without error if not
enough time is given for these operations. The dis-
play may blink briefly.
Payload Meter Power
The payload meter receives its power from the bat-
tery circuit on the truck. Removing battery power
from the payload meter before removing the key
switch and waiting 15 seconds may result in lost haul
cycle data. The payload meter turns itself off approxi-
mately 15 seconds after the key switch power is
removed. Some haul cycle data will be lost if battery
power is removed before waiting 15 seconds. The
payload meter system operates at a nominal voltage
of 24 VDC at 1 to 2 amps, depending on options. The
payload meter is designed to turn itself off if the sup-
ply voltage rises above 36 VDC. The payload meter
is also protected by a 5 amp circuit breaker located in
the junction box.
Power to the load lights comes from the same battery
circuit. The load lights are powered through a relay.
The key switch circuit controls the relay. The load
lights are also protected by a 15 amp circuit breaker
in the junction box.
Load Lights
PLM III uses load lights to indicate to the shovel
operator the approximate weight of the material in
the truck. The load lights are illuminated only when
the brake lock is applied. The lights are controlled by
the payload meter through a series of relays in the
junction box. The payload meter controls the relays
with 24 VDC outputs. A 24 VDC signal from the pay-
load meter powers the relay coil and connects bat-
tery power to the load light. When the relay is not
powered by the payload meter, a pre-warm resistor
connects the load light to a reduced voltage. This cir-
cuit pre-warms the load light filaments and reduces
the inrush current when the light is fully illuminated.
This lengthens the operating life of the load lights.
The load lights progressively indicate to the shovel
operator the approximate weight of the material in
the truck.
A flashing green light indicates the next swingload
will make the measured load greater than 50% of
rated load. A solid green light indicates that the cur-
rent load is greater than 50% of rated capacity.
A flashing amber light indicates the next swingload
will make the measured load greater than 90% of
rated load. A solid amber light indicates that the cur-
rent load is greater than 90% of rated capacity.
A flashing red light indicates the next swingload will
make the measured load greater than 105% of rated
load. A solid red light indicates that the current load is
greater than 105% of rated capacity.
The optimal loading target is a solid green and amber
lights with a flashing red light. This indicates that the
load is between 90% and 105% of rated load for the
truck and the next swingload will load the truck over
105%.
08/06 OM6008