Hardi ISOBUS VT, Operator'S Manual

Page: 55 / 104

7 - Menu 3 Calibration
7.3
Menu 3.2 Flow calibration
The flow transducer can be calibrated theoretically or calibrated with
clean water by using one of the two practical methods.
The practical methods are preferred:
˜
ATTENTION! When changing to nozzles with more than a 100%
increase or decrease in output, it is recommended to re-calibrate
the flow transducer.
˜
ATTENTION! Calibration is recommended to be done at least once during the spraying season. Use the chart “Chart
for recording values” on page 13.4 to record the values.
Menu 3.2.1 Flow constant
When spraying both fertilizer and chemical, HARDI® recommends to use 2 different flow sensor housings in order to get
good pressure regulation. The same flow sensor wheel is used for both flow sensor housings. Flow sensor calibration PPU
must be changed each time flow sensor housings are changed.
Correct flow housing can easily be selected based on:
•
Sprayer boom width.
•
Operator’s typical spray pressure in the field (max. pressure).
•
Nozzle ISO size typically selected by operator.
Approximate PPU values for different flow housings are listed in the
table below. Different flow housings are designated by groove (A).
To change the theoretical flow constant, use the navigation keys to
enter a new PPU value.
˜
ATTENTION! PPU indicates the number of pulses which theoretically come from the flow transducer while 1 gallon of
liquid passes through.
˜
ATTENTION! Entering a theoretical PPU value does not guarantee accuracy. Flow calibration should still be carried out
using one of the practical methods.
Method Calibration time Accuracy
Tank method Time consuming Accurate
Nozzle method Short Inaccurate
Housing Housing identification (A) Flow range Orifice PPU
g/min mm value
S/67 One outside groove 2 - 30 13.5 430.00
S/67 No groove 4 - 70 20.0 215.00
S/67 Two outside grooves 20 - 160 36.0 60.00