Customer settings M0041
Process controller M0742
Internal setpoint 1 M0749
Internal setpoint 2 M0750
Default value:
50.0 %
Setting range:
0.0 ... 100.0 %
8.7.7.
Setting procedure
The setting of the process controller largely depends on the area of controller
application. A PI controller suffices for most applications.
Procedure
1.
Operate the controller as PI controller, i.e. set the parameters as follows:
-
Proportional gain Kp = 1
-
Reset time Ti = 1,000 s
-
Rate time Td = 0
2.
Double proportional gain Kp until the control loop starts to oscillate.
3.
Reduce proportional gain Kp to 60 % of the set value.
4.
Decrease reset time Ti until the error variable equals zero.
8.7.8.
Proportional gain Kp: set
In the event of an error variable, the P portion immediately (i.e. actively) changes
the position value proportionally to the error variable.
If a small error variable already requires a major valve position adjustment, the
proportional gain Kp must be increased.
Information
If the reaction is too extreme (overshoot), the value must be reduced. If the reaction
is too weak, the value must be increased.
Customer settings M0041
Process controller M0742
Proport. gain Kp M0744
Default value:
1.0
Setting range:
0.1 ... 10.0
8.7.9.
Reset time Ti: set
The reset time determines the I portion of the controller. The more inert a system,
the higher this value should be set.
Information
●
Increase Ti in case of propensity for oscillation.
●
Decrease Ti if the reactions are excessively delayed.
●
Starting value for fast processes (e.g. pressure): 10 s
●
Starting value for slow processes (e.g. temperature): 1000 s
Customer settings M0041
Process controller M0742
Reset time Ti M0745
Default value:
1,000 s
(seconds)
Setting range:
1 ... 1000 s
8.7.10.
Rate time Td: set
The rate time determines the D portion of the controller. Typically, no setting is
required here (= 0), since actuator and valve – due to the operating time – cannot
react abruptly to a sudden occurrence of an error variable.
Information
●
Increase Td in case of propensity for oscillation.
●
Initial value for actuators: 0 s
71
Actuator controls
ACV 01.2/ACVExC 01.2 Profibus DP
Application functions