Evoqua DEPOLOX - Controller Modes for Chlorine Control

DEPOLOX
®
Pool Description
WT.050.570.000.DE.IM.0714 23
1.2.4 Controller modes for chlorine control
From firmware version 2.0 of the DEPOLOX
®
Pool, there are two opti-
ons
for setting the concentration of disinfectant:
 Cl2-Single feedback closed loop control
In this mode, the required Cl2 value is held at the setpoint using the
PI single feedback closed loop control (standard chlorine
regulation).
 CEDOX control
In this mode, the chlorine setpoint is continuously optimised using a
PI single feedback closed loop control in order to maintain a cons-
tant redox value. For this procedure, the setpoint entered is not Cl2
as normal, but the required redox potential is set as the setpoint.
A specially developed CEDOX mode calculates the amount of free
chlorine required in the water based on the demand. This internal
chlorine setpoint is used to measure the required quantity of disin-
fectant using the PI single loop feedback controller.
The variable or optimised Cl2 setpoint must remain between the
“Min setpoint” and “Max setpoint” limit values (Menu 1.1.4).
DIN 19643 specifies the following Cl2limits:
Min = 0.30 mg/l and Max = 0.60 mg/l.
Requirement for CEDOX control:
- Chlorine measuring and control
- pH measuring and control
- mV measuring
NOTE
CEDOX control only works if the pH value deviates from the pH setpoint
by no more than 0.30
The CEDOX control system is based on the following principle:
Cl2
PI controller
Xd
deviation
Swimming-
pool
Control loop
X
Chlorine
value
Y
Dosage rate
W
Chlorine
setpoint
Former chlorine control loop
X
Redox value
W
Redox
setpoint
Chlorine Max
Chlorine Min
X
Chlorine value
Characteristic line
system
CEDOX System