10.5 Control parameter [Ti]
The time
[Ti]
is the integral time of the I-
controller (integral controller) in seconds.
The time
[Ti]
defines the time integration
of the control deviation from the control
variable. The smaller the time
[Ti]
, the
greater the effect on the control variable.
An infinitely long time
[Ti]
results in a pure
proportional control.
10.6 Control parameter [Td]
The time
[Td]
is the differentiation time of
the D-controller (differential controller) in
seconds. The D-controller reacts to the
rate of change of the measured value.
10.7
Control parameter [Add.
Basic load]
[Add. Basic load]
is the additive basic
load. The additive basic load should bal‐
ance out a continuous requirement for
feed chemical in order to maintain the set‐
point.
The additive basic load can be set in the
range -100 % … +100 %.
The additive basic load is added to the
control variable determined by the con‐
troller and is effective in both control direc‐
tions. E.g., if the control variable calcu‐
lated by the controller equals
‘
è
y= -10 % and the add. basic load
equals +3 %, then the resulting control
variable = Y= -10 % + (+3 %)= -7 %
è
y= 10 % and the add. basic load
equals +3 %, then the resulting control
variable = Y= 10 % + (+3 %)= 13 %
è
y= 0% and the add. basic load equals
+3%, then the resulting control variable =
Y= 0 % + (+3 %)= 3 %’
10.8
Control parameter
[Checkout time]
The
[checkout time]
should prevent over‐
dosing as a result of a malfunction.
During the
[checkout time]
the control vari‐
able is compared with an adjustable
[threshold]
(= control variable threshold).
Depending on the control direction, you
can set different values for the
[checkout times]
[Checkout time
“
up ]
for
increasing and
[Checkout time
”
down]
for
reducing.
The thresholds depend on the concentra‐
tion of the metered feed chemical. If the
threshold is exceeded, time recording
starts
[(checkout time)]
.
If during the
[checkout time]
the variable
again falls below the threshold, then the
time is again reset to
‘0’
s.
If the control variable remains exceeded
for longer than is permitted by the
[checkout time]
, then control stops imme‐
diately. This function (Control stop) resets
automatically once the threshold is again
undershot.
10.9
Control parameter [max.
ctrl var.]
The
[max. ctrl var.]
specifies the maximum
control variable to be output. This makes
sense if an actuator is over-dimensioned
and must not be opened to 100 %.
10.10 Interference variable
Steadier control of flow processes using a
feedforward control.
Setting the
[Control]
111
To Next Page
Loading...
Need help?
General
