Netafim NETAFLEX 3G, Installation Manual

Page: 24 / 32

24 NETAFLEX™ 3G INSTALLATION MANUAL
CALIBRATION
With the controller set to operate according to EC/pH values - if the EC and pH values measured in the bucket
are within a range of ±30% deviation from the target values, the system will be able to correct them
automatically.
If the values are out of the ±30% range, check the data and consult the agronomist/consultant.
3. Calibration of the NetaFlex™ 3G while irrigating
WARNING
Extreme EC or pH values may damage the crop.
Perform the following procedure only after completing stage 2 above (Simulation test with a 10
liter or 2 US gallon bucket of water) with satisfactory results.
NOTE
The following steps explain the operations to be performed, regardless of the type of controller
used. For the operation of your controller's interface, consult the Controller Manual.
However, since the NMC Pro controller is widely used - its interface screens for the execution of
each step are noted.
NOTE
Before the calibration, confirm that the EC and the pH sensors of the NetaFlex™ 3G have been
calibrated according to the instructions in the EC/pH Installation Manual.
Define the dosing configuration, while the EC and pH controls are in the OFF position (NMC Pro - screen 7.7).
In the EC and pH alarm definitions, set the EC and pH alarm to the OFF position (deactivated)
(NMC Pro - screen 3.6).
Enter the data for the irrigation valves, and the dosing ratio for each dosing channel
(NMC Pro - screens 1.1-1.2-1.3).
Run the program
(NMC Pro - screen 2.2).
Allow a few minutes for the pipes to fill up and the flow rate to stabilize.
Reduce the suction of the dosing channels by adjusting the manual needle valve of each dosing channel
until the "target Rotameter reading" calculated in stage 1 (page 24) is attained.
NOTE
The Rotameter's sacle is calibrated by the manufacturer for measurement of the flow rate of water
(H
2
O). Certain inacuracies may be observed when the flow rate of liquids with different densities,
such as fertilizers and acids, is measured.
Check the appropriate controller screen for the measured EC and pH values
(NMC Pro - hot screen 4)
.
If the desired values have been reached, check opening percentages of the dosing valves.
The EC and pH target values should be attained with the dosing valves opened to 50% - 80% of their capacity.
If the EC and pH target values are attained with the dosing valves opened less than 50%, reduce the
dosing channel suction rate, until the EC and pH target values are reached.
NOTE
Every change in the flow rate of the needle valve must be updated afterwards in the controller
(NMC Pro - screen 7.6).