Payload Meter III - Section 60 OM6009 8/11
Page 60-4
Key Switch Input
PLMIII 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
circuit. The payload meter will remain on for several
seconds after key switch is removed. When the key
switch power is removed, payload meter performs a
series of internal memory operations before turning
itself off. To allow for these operations, the key switch
should 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
display may blink briefly.
Payload Meter Power
The payload meter receives its power from the
battery circuit on the truck. Removing battery power
from the payload meter before removing key switch
and waiting 15 seconds may result in lost haul cycle
data. The payload meter turns itself off approximately
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
24VDC at 1 - 2 amps depending on options. The
payload meter is designed to turn itself off if the
supply voltage rises above 36VDC. 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
PLMIII 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 24VDC outputs. A 24VDC signal from the
payload meter powers the relay coil and connects
battery 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
circuit 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
current 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
current 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%.
To Next Page
Loading...
