Great Plains NTA2007HD Operator Manual - Manual (Page 79)

Great Plains Manufacturing, Inc. Contents Index Adjustments 75
04/04/2011 Contents Index 166-283M
Calibration for Manual Gearbox
Note: For drills with Variable Rate Kit installed, continue
at “Variable Rate (Servo) Calibration” on
page 78.
Complete step 1 through step 13 beginning on page 73.
14. Set gearbox (page 72): Remove the hairpin cotter
securing the gearbox adjustment crank. Rotate crank
until the control arm indicator points to the scale set-
ting that matches the rate from the Seed Rate chart
or as determined by any previous calibration of a
similar material for the same rate.
15. Reinsert the hairpin cotter. Calibration Crank Revolutions
16. Turn the calibration crank, counter-clockwise, for
enough turns to be sure the meter flutes are full and
the system is metering.
17. Stop cranking. Wipe meter doors. Sweep any mate-
rial in the chute into the bag. Empty the bag.
18. Push and then and then
to get to meter calibration.
19. On the seed monitor terminal,
set the monitor to Calibration mode .
enter [ 5 ] for the “# Meter Revs”, and
press the Start softkey .
This “# Meter Revs” parameter does not affect the
monitor calibration because the monitor counts
actual meter shaft revolutions and uses that count to
compute the Calibration Constant.
The “# Meter Revs” parameter is used for a progress
bar displayed during calibration.
20. Turn the hand crank, counter-clockwise, to simulate
meter operation for
1 ⁄
10
ha or
1 ⁄
10
ac. See table at
right.
Note: It is important to turn the calibration crank rapidly.
Use a comfortable speed of 1 to 1 3 ⁄
4
revolutions
per second, which simulates a planting speed
range of 6.7-11.8 kph (4.2-7.3 mph). A longer cali-
bration is always more accurate, especially for low
rates and small seeds.
1 ⁄
10
hectare is easy to cal-
culate with and is a minimum calibration run.
Note: For more accurate results, crank for a full hectare or
acre. With two people, the second person can ob-
serve the revolution count on the seed monitor.
Machine Damage / Invalid Results Risks:
Rotate the hand crank only in the counter-clockwise direction.
Operating in reverse can damage the meter gear box, and
produces low sample sizes leading to incorrect calibration and
excessively high field rates.
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 indica-
tor is closest to the desired setting.
Calibration Crank Revolutions
Limited Flex NTA607HD
Revolutions per Hectare 862
Revolutions per 1/10th hectare 86.2
Calibration Crank Revolutions
Limited Flex NTA2007HD
Revolutions per Acre 349
Revolutions per 1/10th acre 34.9