ABB CM30 - Page 44

ControlMaster CM30 and CM50
Universal process controllers,
1
/4 and
1
/2 DIN 7 Advanced Level
42 IM/CM/ED–EN Rev. B
…Control / …Loop 1 (2) Control / …FeedForward
Mode
Off
Feedforward control is disabled.
Static Gain
Gain applied by FeedForward block is a fixed value set by the user.
Adaptive Gain
Gain applied by the FeedForward block is set by the controller automatically. Adaptive
feedforward can be used even if Adaptive Control (see page
42) has not been enabled. For
Adaptive feedforward to operate, the system must first be tuned using Aututune – see page
19.
Adaptive Gain cannot be used with output tracking or with motorized valve without
feedback. FeedForward (see page
41) with static gain can be used with motorized valve
without feedback. Adaptive Gain cannot be used with pPI control – see page 39.
Source Used to select source of the disturbance variable (DV) – see Appendix A, page 79 for
description of sources.
Gain Sets the gain to be used when in Static Gain mode.
In Adaptive Gain mode this value is set automatically by the controller.
Reset Adaptive FF If the controller is moved to another application, Adaptive feedforward must be reset.
Adaptive Control
Adaptive Control alters the PID parameters automatically (see page 20) if the process changes. It monitors process
performance continuously and updates an internal process model. Based on this process model it calculates the
optimum control parameters and adapts the PID settings accordingly. Changes to the PID settings occur as soon as
the process dynamics change.
Warnings are provided if the control parameters are changed by more than a set amount. This is important to detect
conditions such as a blocked valve that could be interpreted by the adaptive controller as decreased process gain.
Run Autotune (see page 19) to set the initial values for the adaptive controller. In a few cases, Autotune may not work
well, for example in extremely noisy processes. In these cases, provide the adaptive controller with initial values of
Critical Period and Critical Gain by the user – see procedure below.
The adaptive controller uses the Autotune Dynamics setting to determine the optimum PID settings. If the process has
a long deadtime, or a noisy measuring signal, select Deadtime or PI at the Dynamics parameter – see page
20.
The adaptive controller does not work with Motorized Valve without Feedback output types – see Appendix Fig. D,
page 84.
Adaptive Control cannot be used if output tracking mode In Auto is set (see page 46) because the adaptive controller
receives false information.