Commissioning
Liquisys M CCM223/253
44
Hauser
Feedforward control to PID controller
To optimize control systems with very short reaction times, measure the medium flow rate
in addition to the chlorine content. Then apply this flow rate value (0/4 to 20 mA) as
feedforward control to the PID controller.
a0002020
Fig. 33:
Arrangement example for feedforward control oft the flow rate in the main stream to the PID controller(s)
Feedforward control is a multiplying function as illustrated in the figure below (example
with factory setting):
a0005970
Fig. 34: Multiplying
feedforward control
Y
Gain K
infl
X
Current input signal [%]
Z7
Input value, when gain K
infl
= 1
CAL
REL
REL1
REL1
ALARM
REL2
REL2
E
mg/l
25.0 °C
0.42
F
4 ... 20 mA
Cl
2
pH
1
2
3
4
5
6
1
Measuring water extraction point
4
Flow meter
2
Static mixer
5
Flow assembly CCA250
3
Injection points
6
Liquisys M CCM253
1
0
20
40
60
80
100
Z7
1.5
0.5
Y
X
Summary of Contents for Liquisys M CCM223
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