Step 22. otherwise – Great Plains NTA2007 Material Rate User Manual
Page 13
Great Plains Manufacturing, Inc.
Setting Meter Rate
11
2012-01-03
167-085B
18. Refer to the Seed Rate Chart (or Fertilizer Rate
Chart for Seed or Fertilizer Rate gearbox setting
values for the target rate.
19. Determine the amount of rate change for each
degree of control arm rotation from the target setting.
If the calibrated rate was
higher than target (as in our example),
examine lower gearbox setting values.
If the calibrated rate was
lower than target,
examine higher gearbox setting values.
20. Adjust the control arm by the number of degrees
needed to adjust for the calibration difference.
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 corrected setting.
21. Run the calibration again, starting at step 10, using
the new Variable Rate Gearbox scale setting.
This validates the gearbox adjustment, and
establishes a new, more precise Calibration
Constant.
22. With the present meter satisfactorily calibrated, re-
mount the final drive gear removed from the other
hopper.
23. Repeat the calibration procedure for the other
hopper, starting at step 1.
If only planting from a single hopper, see “Single
Hopper Operation” in the air cart Operator Manual
for methods of disabling the meter on the hopper not
in use.
24. Remove and store the calibration crank.
TargetRate
Metric Example:
Initial Variable
Rate Gearbox
Setting: 62
183.5
59
2783
189.4
60
2787
195.4
61
2792
201.3
62
2797
207.4
63
2802
TargetRate
USc Example:
Initial Variable
Rate Gearbox
Setting: 38
56.9
63.7
35
77538
60.4
67.6
36
77591
63.9
71.7
37
77640
67.6
75.8
38
77683
71.4
80.0
39
77723
Metric Example:
USc Example:
1 degree lower reduces rate by
201.3 - 195.4, or 5.9 Kg
67.6-63.9, or 3.7 lbs
2 degrees lower reduces by
201.3 - 189.4, or 11.9 Kg
67.6-60.4, or 7.2 lbs
3 degrees lower reduces by
201.3 - 183.5, or 17.8 Kg
67.6-56.9, or 10.7 lbs
Metric Example:
USc Example:
The calibration difference was:
17 Kg
8 pounds.
Adjusting down 3 degrees
would slightly over-correct,
at a difference of 17.8 Kg
Adjusting down 2 degrees
would correct by 7.2
pounds, but adjusting by 3
would over-correct to 10.7
lbs.
So adjust the gearbox
setting to just under 3
degrees lower, to a final
scale setting of:
So adjust the gearbox
setting to just over 2
degrees lower, to a final
scale setting:
slightly above 59
slightly below 36