ProMinent DULCOMETER - Control parameter [Setpoint]

smaller (proportional relationship). If the
setpoint is nearly reached, then the con‐
trol output is nearly 0 %. However the set‐
point is never exactly reached. Conse‐
quently a permanent control deviation
results. When stabilizing large changes,
excess oscillations may occur.
PI controller:
This controller type is used with a non-
integrating control path (e.g. flow neutrali‐
sations). Here excess fluctuation must be
avoided. No permanent control deviation
must occur. The setpoint must always be
adhered to. A constant addition of
metering chemicals is required. It is not a
malfunction when the controller does not
stop metering when the setpoint is
reached.
PID controller:
This controller type has the properties of a
PI controller. Due to the differentiating
control part [D] , it also offers a certain
level of foresight and can react to forth‐
coming changes. It is used when meas‐
urement spikes occur in the measurement
curve and these must be quickly regulated
out.
10.2
Control parameter
[System response]
You can set the system response of the
controller under the menu option
[System response] .
Standard
The controller reacts with its P, PI or PID
system response as described in
Ä Chapter 10.1 ‘Control parameter [Type]’
on page 108 .
[Standard] is the selection for [1-way ]
controlled processes.
[Dead zone]
The [Dead zone] is defined by an upper
and lower setpoint. The [dead zone] only
operates with a [2-way] [control] , if an
actuator is available for each direction.
The
[dead zone] should have the effect of
preventing the control path from starting to
oscillate. If the measured value lies within
both the setpoints, then no control of the
actuators takes place. In this case even a
PI/PID controller does not activate its
actuators. The
[dead zone] is used with a
[2-way] neutralisation.
10.3
Control parameter [Set‐
point]
The setpoint specifies the target value for
control. The controller attempts to main‐
tain the deviation between the setpoint
and the actual value (measured value) as
close to
‘0’ as possible.
Setting the [Control]
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