Great Plains YP1630F-1670 Material Rate - Manual (Page 23)

Great Plains Manufacturing, Inc. Contents Appendix Fertilizer Rate 21
2012-12-04 Contents Appendix 401-832B
The right column contains the starting values of an
example for the following steps, in Metric and U.S.
customary (“USc”) units.
12. Accurately weigh the bag plus material. Subtract the
empty bag weight to determine the application rate
for
1 ⁄
10
hectare (or
1 ⁄
10
acre).
13. Multiply the sample size by 10 to determine
application rate per hectare (acre) at the current
variable rate gearbox setting.
If the calibrated rate matches the target rate, skip to
step 18. Otherwise…
14. Determine a ratio to use for a new setting.
Note: The effect of the gearbox adjuster is nearly linear in
the 30 to 70 range of the scale.
15. Subtract the calibrated rate per hectare (or acre)
from the target rate to determine a correction
difference.
16. Adjust the control arm by the number of degrees
needed to adjust for the calibration difference.
17. Run the calibration again, starting at step 9, using
the new Variable Rate Gearbox scale setting. This
validates the gearbox adjustment.
18. Remove and store the calibration crank. Wipe down
the calibration door, seal and lower face of meter.
Close the calibration door. Empty the bag into the
hopper.
This completes fertilizer rate calibration.
Metric Example:
Application
FieldRate :
104 kg/ha
Density AdjustedRate :
83.2
USc Example:
Application
FieldRate :
93 pounds per acre
Density AdjustedRate :
74.4
Initial (adjusted) Variable Rate Gearbox setting:
39 39
Empty Calibration BagWeight :
1.52 Kg 3.36 lbs
Metric Example:
GrossWeight is:
11.2 kg
SampleWeight =
11.2 - 1.53
which is:
9.67 Kg
USc Example:
GrossWeight is:
8.6 pounds
SampleWeight =
12 - 3.36,
which is:
8.6 pounds
SampleWeight GrossWeight BagWeight – =
Metric Example:
CalibratedRate =
6.67 × 10
which is:
96.7 kg/ha
USc Example:
CalibratedRate =
8.6 × 10,
which is:
86 lbs/ac
This is lower than our target field rate of:
104 kg/ha 93 lbs/ac
CalibratedRate SampleWeight 10 × =
Metric Example:
FieldRate :
104
CorrectionFactor =
104 ÷ 96.7,
which is:
1.08 (108%)
USc Example:
FieldRate :
93
CorrectionFactor =
93 ÷ 86,
which is:
1.08 (108%)
The calibration run metered too little.
You must raise the gearbox setting to compensate.
CorrectionFactor
FieldRate
CalibratedRate
----------------------------------- =
Note: The rate of the arm adjusting crank is more than
one scale degree per turn, and the crank can only
be pinned at quarter turns. Pin it when the indicator
is closest to the new setting.
Example:
PriorGearboxSetting :
39
NextGearboxSetting =
39
× 1.08
which is:
42
NextGearboxSetting PriorGearboxSetting CorrectionFactor
Ч
=