Great Plains NTA2007 Material Rate - Manual (Page 12)

10 Great Plains Manufacturing, Inc. Contents Appendix VRG Air Drills
167-085B Contents Appendix 2012-01-03
13. Wipe all the material off the flanges around the
meter doors and capture that material in the
calibration container.
The right column contains an example for the following
steps, in U.S. customary (“USc”) and Metric units.
14. Accurately weigh the container plus material.
Subtract the empty container weight to determine
the application rate for
1 ⁄
10
hectare (or
1 ⁄
10
acre).
15. Press the Stop softkey on the monitor
and enter the sample net weight (SampleWeight).
The monitor responds with a Calibration Constant.
Push the Save softkey to accept this
value.
16. 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 22. Otherwise…
17. Subtract the calibrated rate per hectare (or acre)
from the target rate to determine a correction
difference.
Metric Example:
Wheat, High Rate,
2 Stars
Target Seed Rate:
200 Kg/ha
USc Example:
Wheat, High Rate,
2 Stars
Target Seed Rate:
67.6 pounds per acre
Initial Variable Rate Gearbox setting:
62 38
Empty Calibration Bag Weight:
1.52 Kg 3.36 lbs
Metric Example:
MeasuredWeight is:
23.3 Kg
SampleWeight =
23.3 - 1.53
which is:
21.7 Kg
USc Example:
MeasuredWeight is:
10.92 pounds
SampleWeight =
10.92 - 3.36,
which is:
7.56 pounds
SampleWeight MeasuredWeight ContainerWeight – =
Metric Example:
CalibratedRate =
21.7 x 10
which is:
217 Kg/ha
USc Example:
CalibratedRate =
7.56 x 10,
which is:
75.6 lbs/ac
This is higher than our target rate of:
200 Kg/ha 67.6 lbs/ac
CalibratedRate SampleWeight 10 ×
=
Metric Example:
TargetRate =
200
RateDifference =
200 - 217,
which is:
-17 Kg
USc Example:
TargetRate =
67.6
RateDifference =
67.6 - 75.6,
which is:
-8 pounds
The calibration run metered too much.
You must lower the gearbox setting to compensate.
RateDifference T etR arg ate CalibratedRate – =