OEM OPM223 Operating Instructions Manual page 33

OPM223/253
Feedforward control to PID controller
For control systems with very short reaction times, it can be useful to also apply the flow rate,
if it is fluctuating, to the controller to optimise the control process.
Fig. 25:
1 Measuring water extraction point
2 Static mixer
3 Injection points
4 Flowmeter
Feedforward control is a multiplying function as illustrated in the figure below (example with
factory setting):
1,5
0,5
Fig. 26:
Y Gain K
X Current input signal [%]
1
8
Sample arrangement for feedforward control of the flow in the main stream to the PID controller
Y
1
0 20
Multiplying feedforward control
infl
2
7
0.42 mg/l
25.0 °C
REL 1
ALARM
REL 2
CAL REL
REL 1
E
REL 2
4 ... 20 mA
5 Alkali
6 Acid
7 Transmitter OPM253
8 OPA250 with OPS11
40 Z7 60
Operation
3
4
F
6
5
C07-OPM2x3xx-05-06-00-xx-002.eps
80 100 X
C07-OPM2x3xx-05-06-00-de-003.eps
33