ABB ECA06 - Page 145

Chapter 3: Configuration 3.6 Setting the Configuration
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Adaptive Gain
Adaptive Feed Forward will always work even if the controller has not been
configured for Adaptive Control.
To enable Adaptive Feed Forward set the parameter Mode to AdaptiveGain. For
the Adaptive Feed Forward function to work, you must tune the system using the
Autotuner. The Autotuner gives the Feed Forward function start information.
Notes:
• Adaptive Feed Forward cannot be used with output signal Tracking, or with
Three State Pulse output with no actuator feedback
• Feed Forward (Mode = StaticGain) can be used with Three State Pulse with no
actuator feedback.
• Adaptive Gain will not work together with pPI control.
Autotuner
Autotuning is an aid which permits automatic setting of the controller PID
parameters. It uses a relay-type function with hysteresis which initiates a
controlled oscillation in the process.
When the function is enabled the autotuning procedure starts by inserting a step
in the output signal so that the Process Value begins to diverge from the Set Point.
Because the relay function is controlling the process during autotuning, self-
oscillation is induced so that the output signal alternately exceeds and falls below
the original value by a defined amplitude. The Autotuner itself adjusts this
amplitude so that the Process Value will not be greater than a level which is
necessary for the process response to be isolated from process and measuring
noise (the oscillation amplitude is roughly comparable to the process noise level).
By measuring the process response the Autotuner can identify the process
dynamic characteristics during autotuning. When the parameters are considered
reliable the autotuning process stops. New PID parameters are calculated and
stored in the controller.
The autotuning function has certain similarities to the manual Ziegler Nichols
method. However, the Autotuner has control over the process oscillation
amplitude which results in considerably less disturbance to the process.
Available in
ECA06 ECA60 ECA600 EMA60
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