Komatsu WA600-8 Operation & Maintenance Manual page 508

HANDLE LOAD METER
NOTES ON USING LOAD METER AT OPTIMUM ACCURACY
Calibration
1.
Necessity
The machine monitor has registered maps which show the relationship between lift cylinder pressure and
loaded weight when the bucket is loaded with no load, 1/2 of rated load, and rated load.
To use the load meter at a desirable accuracy when the machine has individual variation in performance or
the bucket has been repaired, the saved maps need to be corrected in advance. This correcting function is
called the calibration.
The calibration is needed for the following cases.
1)
When the new machine is delivered
2)
When the boom is replaced
3)
When the machine monitor is replaced
4)
When the pressure sensor or boom angle sensor are replaced
5)
Periodically (once in 3 months)
For 2) to 5), reset the current calibration data first, and then perform the calibration.
2.
Precautions for calibration
Note the following points when performing the calibration.
• The loaded weight is calculated from the lift cylinder pressure (at bottom and head), boom angle, and
angular speed.
• Mass of weight: Load the bucket with following weight or equivalent handled material before starting
the calibration.
Calibration at 1/2 of rated load
Calibration at loaded (rated load)
Note: If the weight used diverges far from the above range, the maps cannot be corrected properly, and
the accuracy of the measurement will be reduced.
• Shape of loaded material: Perform the loaded calibration with the loaded material in the same shape
as that during actual operation.
• Warm-up operation: Perform normal operation (including boom RAISE and LOWER) for 10 minutes or
more (30 minutes or more is preferable) as a warm-up operation in order to raise the hydraulic oil tem-
perature to the normal operation range.
• Boom RAISE speed: To keep the rising speed of boom constant, perform this with boom control lever
at boom RAISE detent position.
• Accelerator pedal: Depress the accelerator pedal to the same position as that in the actual operation.
Maintain a constant throttle position without changing it during calibration.
• Bucket posture: Perform the measurement with the bucket tilted back fully. Perform the calibration with
the bucket tilted back fully as well.
For details of the calibration procedure, see "CALIBRATE WITH EMPTY LOAD (6-59)", "CALIBRATE AT 1/2
OF RATED LOAD (6-60)", and "CALIBRATE AT RATED LOAD (6-62)".
During measurement
1.
Shape of loaded material
If the center of gravity of the load varies (especially fore-and-aft direction), the lift cylinder pressure also var-
ies, and the accuracy of the measurement will be reduced.
Perform the loaded calibration with the loaded material in the same shape as that during measurement.
2.
Warm-up operation
When the hydraulic oil temperature is low, the accuracy of the measurement will be reduced.
Perform the normal operation (including boom RAISE and LOWER) for 10 minutes or more (30 minutes or
more is preferable), and then start the measurement.
6-46
Empty calibration
ATTACHMENTS AND OPTIONS
Empty bucket
6.0 to 7.0 t
11.5 to 14.5 t