ABB ECA06 - Page 217

Appendix A: Application Examples A.1 Level Control with Feed Forward and Gain Scheduling
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Feed Forward
The Feed Forward mode must be set to StaticGain. The signal that is fed forward
is the flow measured by the transmitter FT1, which is connected to AI2. The Gain
must be tested by trial and error but in this example it is set to 2.
1 Control → Parameters → Feed Forward→ Mode = StaticGain.
2 Control → Parameters → Feed Forward → FeedForwardSignal =
AI2[Value].
3 Control → Parameters → Feed Forward→ Gain = 2.
Gain Scheduling
The Gain Scheduling must be enabled and the limits set. The non-linearity in the
control valve in this example is divided into three ranges with limits at 40% and
60%.
Absolute Alarm 1
HiLimit
80%
Cancel
OK
Feed Forward
Mode
Static Gain
Cancel
OK
AI2: Level
FeedForwardSignal
AI2[Value]
Cancel
OK
Feed Forward
Gain
2
Cancel
OK