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OPM223/253
Neutralisation controller
During neutralisation control, the pH value of a medium is kept constant by dosing acid and
alkali. Two separate actuating signals are required for this task, one for acid and one for alkali.
The neutralisation controller is a controller with two relay contacts and is specially designed for
this task. The P(ID) controller is available as the controller.
The values for the control gain K
T
and derivative action time T
n
The "neutral Zone" is located between the set values 1 and 2. There is no acid or alkali dosing
(Y = 0, see Fig. 37) in the "neutral zone" with a controller without integral components (P, PD).
In the case of a controller with an integral component (PI, PID), there is constant alkali/acid
dosing (Y
process type (inline/batch).
The "neutral zone" can be shifted as desired in the X direction via set point 1 and 2.
!
Note!
Neutralisation control is only possible with relays 1 and 2.
Fig. 37:
1
Neutral zone
2
Set point 1
3
Set point
Coding
Field
RELAY function
R
group
Select contact to be
R1
configured
Configure limit
contactor for pH/
R2 (1)
ORP measurement
p
apply to both controllers (see "P(ID) controller" section).
v
= Y
). The behaviour of the I-component within the neutral zone depends on the
new
old
Y [%]
100
50
0
Control characteristic of a proportional neutralisation controller
Setting range
(Factory settings, bold)
Rel1
Rel2
Rel3
Rel4
LC PV = limit contactor
pH/ORP (1)
LC C = limit contactor T (2)
PID controller (3)
Timer (4)
Clean = Chemoclean (5)
Neutra controller (6)
for acid and alkali can be set separately. Integral action time
1
2
3
4
6
5
4
Set point 2
5
Control contact 1 for alkali
6
Control contact 2 for acid
Display
R
RELAIS
Rel1
R1
Sel.Relay
LC PV
R2
Sel.Type
Operation
X
C07-OxM2x3xx-05-06-00-xx-009.eps
Info
Relay contact settings.
Rel3 (water) and Rel4 (cleaner) are only
available with the relevant version of the
transmitter.
If Chemoclean is used as the cleaning
method, Rel4 is not available.
PV = process value
If Rel4 is selected in the R1 field,
Clean = Chemoclean cannot be
selected.
By confirming with ENTER, another
relay function already switched on is
switched off and its settings are reset to
the factory settings.
49
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