OM6009 8/11 Payload Meter III - Section 60
Page 60-7
PAYLOAD OPERATION & CALCULATION
Description of Haul Cycles
The typical haul cycle can be broken down into eight
distinct “stages” or “states”. Each state requires the
payload meter to make different calculations and
store different data.
1. Tare Zone
2. Empty
3. Loading
4. Maneuvering
5. Final Zone
6. Hauling
7. Dumping
8. After Dump
A new haul cycle is started after the load has been
dumped from the previous cycle. The payload meter
will stay in the after dump state for 10 seconds to
confirm that the load has actually been dumped. If
the current payload is less than 20% of rated load,
the payload meter will switch to the tare zone and
begin calculating a new empty tare. If, after dumping,
the payload has not dropped below 20% of rated
load the meter will return to the maneuvering or
hauling states. In this case, the false_body_up flag
will be recorded in the haul cycle record.
While in the tare zone state, and moving faster than 5
kph (3 mph), the payload meter calculates the empty
sprung weight of the truck. This tare value will be
subtracted from the loaded sprung weight to
calculate the final payload. The payload meter will
switch from the tare zone or empty to the loading
state if swingloads are detected. By raising the dump
body while in the empty state the payload meter can
be manually switched back to the tare zone to
calculate a new tare.
From the empty state, the payload meter will switch
to the loading state through one of two means. If the
brake lock is applied, the payload meter will be
analyzing the suspension pressures to detect a
swingload. If a swingload is detected, the meter will
switch to the loading state. The minimum size for
swingload detection is 10% of rated load. Swingload
detection usually takes 4-6 seconds. The second
method to switch from empty to loading is through
continuous loading. This can happen if the brake lock
is not used during loading. If the load increases
above 50% of rated load for 10 seconds without the
brake lock applied, the meter will switch to loading
and record the continuous_loading flag in the haul
cycle.
The payload meter switches from loading state to
maneuvering state as soon as the truck begins
moving. The maneuvering zone is 160 m (0.1 mile)
and is designed to allow the operator to reposition
the truck under the shovel. More payload can be
added anytime within the maneuvering zone. Once
the truck travels 160 m (0.1 mile), the payload meter
switches to the final zone and begins calculating
payload. If the body is raised while the payload meter
is in the maneuvering state, the no_final_load flag
will be recorded in the haul cycle record, no payload
will be calculated, and the meter will switch to the
dumping state.
While in the final zone, and moving faster than 5 kph
(3 mph), the payload meter calculates the loaded
sprung weight of the truck. The same advanced
algorithm is used to calculate the empty and loaded
sprung weights. The payload meter will switch from
the final zone to the dumping state if the body-up
signal is received. If the truck has moved for less
than one minute in the final zone, the payload meter
will calculate the final payload using an averaging
technique which may be less accurate. If this
happens, the average_load flag will be recorded in
the haul cycle.
The payload meter switches to the dumping state
when the dump body rises. The payload meter will
switch from dumping state to after dump state when
the dump body comes back down.
From the after dump state, the payload meter will
switch to one of three states:
1. If the average payload is greater than 20% of
rated load and no final payload has been
calculated, the payload meter will return to the
maneuvering state. After the truck travels 160m
(0.1 mile) the meter will switch to the final zone
and attempt to calculate the payload again. The
false_body_up flag will be recorded in the haul
cycle record.
2. If the average payload is greater than 20% of
rated load and the final payload has been
calculated, the payload meter will switch back to
the hauling state. The false_body_up flag will
be recorded in the haul cycle record.
3. If the average payload is less than 20% of rated
load, the payload meter will switch to the tare
zone and begin to calculate a new empty tare.
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