March 2020
www.farmscan.com.au
AM-7500-5
53
Fine Tuning Calibration Factors
FINE TUNING CALIBRATION FACTORS
Calibration factors can be fine-tuned by using the two tenths of a hectare test. This test will run the
selected drive for 2/10th of a hectare while stationery. Product should be caught and weighed to check bin
calibration factors are correct.
1.
Fill the bin with a pre-measured quantity of product
2.
Return to
Bin/Tank X
3.
Select
Test
4.
Select
2/10
th
’s Ha Test
5.
Select the
Simulation Speed
and enter your typical seeding speed
6.
Check the metering system is primed with product and ready to be caught by weighing
i.
Return the product to the bin.
7.
Press the
START CALIBRATION
i.
Product will now start to flow at the simulated speed & rate
8.
After metering the pre-measured quantity, press
STOP
9.
Weigh the product caught
10.
Enter the weight in the
Enter Weight (kg)
11.
Press the
Tick
12.
The calibration factor will now be updated
13.
Press the
Tick
to exit
Example
If the bin rate was set to 50kg/ha, after a 2/10
th
ha test, 10kg of product should have been metered.
Assuming the “CAL SPEED” was correct during calibration (see step 3) and the metering system is linear through
its entire range. If the metered quantity is not correct apply the formula below. Using the above example, say
11.4kg is metered instead of 10kg and 48.5pulses/kg was the product calibration factor.
Formula
new calibration factor = expected quantity x old calibration factor ÷ actual quantity
Expected quantity
=
10 kg
(desired quantity in kg or litres)
Old calibration factor =
48.5 pulses/kg
(pulses per kilo or pulses per litre)
Actual quantity
=
11.4 kg
(pre-measured weight or volume)
New calibration factor =
10 / 11.4 x 48.5 pulses/kg
= 42.54 pulses/kg
•
Metering will ONLY occur if the “FAN” alarms are disabled/critical or the fan is operating with the
low and high alarm points.
•
The 2/10
th
ha test will NOT work on ground drive machines i.e. gearbox drive and gate actuator
drives.
