Hach-Lange WTOS P-RTC - Manual (Page 15)

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Section 4 Parameterization and operation
4.1 Open-loop control and closed-loop control programs
Four different programs are provided to enable optimal
adaptation to local conditions and to the available measurement
signals.
Programs 3 and 4 have various functions depending on whether
open-loop control or closed-loop control is selected.
4.1.1 Open-loop control
For the open-loop control of precipitant dosing, the measuring
point for phosphate concentration is upstream of the precipitant
dosing point.
4.1.1.1 Open-loop control according to phosphate concentration profiles
Program 1
Load-proportional open-loop control:
• Specified profile of the phosphate concentration in the reactor
inlet
• Specified profile for the flow rate
Program 2
Load-proportional open-loop control:
• Specified profile of the phosphate concentration in the reactor
inlet
• Flow rate measured value
Note: The prerequisite for this program is that the flow rate
measurement signal is valid. "Valid" means that the signal is present at
the relevant input.
4.1.1.2 Open-loop control according to measured phosphate values
Program 3
Load-proportional open-loop control:
• Measured value of the phosphate concentration in the reactor
inlet
• Specified profile for the flow rate
Note: The prerequisite for this program is that the PO
4
-P measurement
signal is valid. "Valid" means that the signal is present at the relevant
input.
Program 4
Load-proportional open-loop control:
• Measured value of the phosphate concentration in the reactor
inlet
• Flow rate measurement
Note: The prerequisite for this program is that both measurement signals
are valid. "Valid" means that the signal is present at the relevant input.