Liquisys M CPM223/253
Operation
Hauser
55
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
p
for acid and alkali can be set separately. Integral action time T
n
and derivative action time T
v
apply to both controllers (see "P(ID) controller" section).
The "neutral Zone" is located between the set values 1 and 2. There is no acid or alkali dosing
(Y = 0, see Fig. 45) 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
new
= Y
old
). The behaviour of the I-component within the neutral zone depends on the 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.
C07-CxM2x3xx-05-06-00-xx-009.eps
Fig. 45:
Control characteristic of a proportional neutralisation controller
1
2
3
Neutral zone
Set point 1
Set point
4
5
6
Set point 2
Control contact 1 for alkali
Control contact 2 for acid
Y [%]
X
100
50
0
1
2
3
4
5
6
Coding
Field
Setting range
(Factory settings, bold)
Display
Info
R
RELAY function
group
Relay contact settings.
R1
Select contact to be
configured
Rel1
Rel2
Rel3
Rel4
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.
R2 (1)
Configure limit
contactor for
pH/redox
measurement
LC PV = limit contactor
pH/redox
(1)
LC C = limit contactor T (2)
PID controller (3)
Timer (4)
Clean = Chemoclean (5)
Neutra controller (6)
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.
R211
Switch function of R2
(1) off or on
Off
On
All the settings are retained.
R
RELAIS
R1
Sel.Relay
Rel1
R2
Sel.Type
LC PV
R211
Function
off
