Hach-Lange RTC112 SD-Module - Manual (Page 29)

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Parameterization and operation
4.6 PRESELECT PROG
4.6.1 POLYMER DOSING CONTROL
Based on the measured feed flow rate [m³/h] and the measured
TSS concentration [g/L] from the influent, the polymer dosing rate
[L/h] is calculated such that the setpoint corresponds to the
specific polymer dosing rate [g/kg].
Note: This open-loop control mode can only be activated if FEED FLOW
CONTROL is deactivated.
Note: The polymer flow rate is controlled via the RTC.
4.6.2 FEED FLOW CONTROL
Based on the measured TSS concentration [g/L] and the
specified polymer dosing rate [L/h], the feed flow rate is
calculated such that it corresponds with the specific polymer
dosing rate [g/kg] (FACTOR POLYMER DOSING).
Note: This open-loop control mode can only be activated if POLYMER
DOSING CONTROL is deactivated.
Note: The feed flow rate is controlled via the RTC.
4.6.3 CLOSED-LOOP EFFLUENT CONTROL
If activated, the specific polymer dosing rate FACTOR POLYMER
DOSING is adjusted based on the difference between the target
and actual TSS concentration in the dewatered sludge.
If FEED FLOW CONTROL is activated, the TSS load fed with the
sludge thickening is adjusted based on the difference between
the target and actual TSS concentration in the filtrate.
Note: This closed-loop control can only be activated if POLYMER
DOSING CONTROL (
section 4.6.1 ) or FEED FLOW CONTROL
( section 4.6.2 ) is activated.
4.6.4 CLOSED-LOOP FILTRATE CONTROL
If activated, the specific polymer dosing rate FACTOR POLYMER
DOSING is adjusted based on the difference between the target
and actual TSS concentration in the filtrate/centrate.
The change in the specific dosing rate affects the polymer dosing
rate [L/h] in the POLYMER DOSING CONTROL module or
affects the feed flow rate in the FEED FLOW CONTROL module.
Note: Activation and deactivation of CLOSED-LOOP EFFLUENT
CONTROL and CLOSED-LOOP FILTRATE CONTROL have to be
prepared by executing the relevant *bat-files on the RTC CF-card (see
section 2.5.3 ).