Komatsu 830E-AC Shop Manual page 842

Loading Conditions
The final load calculation of the PLMIII system is not
sensitive to loading conditions. The final load is cal-
culated as the truck travels away from the shovel.
Variations in road conditions and slope are compen-
sated for in the complex calculations performed by
the payload meter.
Pressure Sensors
Small variations in sensors can also contribute to
payload calculation error. Every pressure sensor is
slightly different. The accuracy differences of individ-
ual sensors along the range from 0 to 4000 psi can
add or subtract from payload measurements. This is
also true of the sensor input circuitry within individual
payload meters. These differences can stack up 7%
in extreme cases. These errors will be consistent and
repeatable for specific combinations of payload
meters and sensors on a particular truck.
Swingloads
Swingload calculations can be affected by conditions
at the loading site. Parking the truck against the berm
or large debris can cause the payload meter to inac-
curately calculate individual swingloads. While the
PLMIII system uses an advanced calculation algo-
rithms to determine swingloads, loading site condi-
tions can affect the accuracy.
Speed and Distance
The payload meter receives the same speed signal
as the speedometer. This signal is a frequency that
represents the speed of the truck. The payload meter
uses this frequency to calculate speeds and dis-
tances. The meter assumes a single value for the
rolling radius of the tire. The rolling radius may
change at difference speeds by growing larger at
higher speeds. The actual rolling radius of the tire will
also change between a loaded and empty truck. The
payload meter does not compensate for these
changes.
NOTE: Earlier 730E & 830E models are subject to
incorrect speed data due to electrical interference.
The incorrect speeds are generated while the truck
is stopped. An attenuator was added to newer
production models to prevent this error from
occurring. A kit was released to update older PLMIII
systems with the attenuator. Consult your area
service representative for details.
M20-14
HAUL CYCLE DATA
PLMIII records and stores data in its on-board flash
memory. This memory does not require a separate
battery. The data is available through the download
software.
PLMIII can store 5208 payload records. When the
memory is full, the payload meter will erase the old-
est 745 payload records and continue recording.
PLMIII can store 512 alarm records in memory.
When the memory is full, the payload meter will
erase the oldest 312 alarm records and continue
recording.
All data is calculated and stored in metric units within
the payload meter. The data is downloaded and
stored in metric units within the Paradox database on
the PC. The analysis program converts units for dis-
plays, graphs and reports.
The units noted in the Table 1 are the actual units
stored in the data file. The value for the haul cycle
start time is the number of seconds since January 1,
1970 to the start of the haul cycle. All other event
times are referenced in seconds since the haul cycle
start time. The PC download and analysis program
converts these numbers into dates and times for
graphs and reports.
Payload Meter III 02/05 M20008