NMC-PRO Installation Manual
117Page
Passive: The channel does not respond to changes in measured EC/pH, meaning it will be opened as
set in the dosing program regardless of the EC/pH values.
Alkali: The channel is used to increase measured pH, meaning it will be opened more when the
measured pH is lower than the set pH.
Note: If EC/pH control is off, or the channel is used for proportional injection only (for example in order to inject
chemicals) set reaction to passive.
• High %: set an injection percentage limit. This percentage will limit the deviation from set dosing recipe when
NMC-Pro is injecting more than specified in order to try and reach the target EC/pH values.
• Low %: set an injection percentage limit. This percentage will limit the deviation from set dosing recipe when
NMC-Pro is injecting less than defined in order to try and reach the target EC/pH values.
• V/P(L/G): This parameter will be disabled when operating by Liter/Pulse. Define the volume per pulse of the
dosing meter (liters or gallons). Only required when using a dosing meter for measurement and alarm
purposes. When using a dosing meter for control purposes the volume per pulse of the dosing meter should
be defined on the Ratio column. The letter between the brackets indicates whether the volume units are in
Liter or Gallon.
11.6.1 Calibrating the Analog Dosing Valve
The following section details how to calibrate the dosing valve when using Venturi Pumps.
1. Ensure that all dosing channels are physically connected to the fertilizer tanks.
For purposes of calibrating the dosing, the tanks can be filled with water.
2. Verify that the needle valve is completely open (100%).
3. Go to Testing > Relays.
4. Manually operate the Irrigation Program and Dosing Booster.
5. Go to Test > Analog Output.
a. Set the status as Manual.
b. Define all openings as 25%.
c. Check the injection rate/fertilizing rate on the Rotameter.
Example: If the observed rate is 100 liters per hour when set at 25%, the maximum rate should be 400
liters per hour (formula: 100 / 0.25 = 400).
Even when the Venturi capacities are the same, and the opening percentage is the same for each valve, there can
be small variations in the actual flow rate.
Be aware that when you use water to calibrate the Rotameter valves, there can different reading when fertilizer is
actually used.
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