Process Controller Activation; Process Controller: Set Modulating Behaviour - AUMA AC 01.2 Manual

Application functions
8.5.1.

Process controller activation

Function not active
Function active
8.5.2.

Process controller: set modulating behaviour

P controller
P controller application
PI controller
PI controller application
PID controller
58
Required user level: Specialist (4) or higher.
Device configuration M0053
Application functions M0178
Activation M0212
Process controller M0741
Default value: Function not active
Setting values:
<Process controller> function deactivated.
<Process controller> function activated.
Three controller types are available to ideally adapt the modulating behaviour of the
process controller to the respective application.
Customer settings M0041
Process controller M0742
Modulating behaviour M0887
Default value: PI controller
Setting values:
P controllers immediately react to an error variable (i.e. actively) and amplify the
input signal (error variable) proportionally to the set amplification. Setting parameter:
Proport. gain Kp M0744
Figure 38: Step response of P controller
For uncritical closed-loop applications allowing to accept continuous error variables
in the event of failures, e.g. pressure, flow, filling level and temperature control.
PI controllers consist of a P fraction immediately (actively) reacting to an error variable
and an I fraction for chronological integration of the input signal (error variable). Due
to the additional time constant of the I fraction, the output value takes more time to
reach the target status (i.e. inertia of control loop response) whereas positioning
accuracy increases at the same time (lower control deviation). Parameters for setting
the time constant: Reset time Ti M0745
Figure 39: Step response of PI controller
Quick control circuits not allowing continuous error variables, e.g. pressure,
temperature and ratio control.
Compared to the PI controller, the PID controller has an additional D fraction
accounting for changes in the error variable (change rate). The D fraction quickly
reacts to changes, even to minor error variables with large output values. Parameter
for setting the D fraction: Rate time Td M0746
Actuator controls
AC 01.2/ACExC 01.2 Profinet