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NOTE
Parameters 437-444 are only used
if in parameter 100 Configuration a
selection has been made of Process
regulation, closed loop. [3].
437 Process PID normal/inverse control
(PROC NO/INV CTRL)
Value:
Normal (NORMAL)
Inverse (INVERSE)
Function:
It is possible to choose whether the process regulator
is to increase/reduce the output frequency if there
is a deviation between the reference/setpoint
and the actual process mode.
Description of choice:
If the variable frequency drive is to reduce
the output frequency in case the feed-
back signal increases, select Normal [0].
If the variable frequency drive is to increase the
output frequency in case the feedback signal
increases, select Inverse [1].
438 Proces PID anti windup
(PROC ANTI WINDUP)
Value:
Not active (DISABLE)
Active (ENABLE)
Function:
It is possible to select whether the process regulator is
to continue regulating on a deviation even if it is not
possible to increase/reduce the output frequency.
Description of choice:
The factory setting is Enable [1], which means that
the integration link is initialized in relation to the
actual output frequency if either the current limit, the
voltage limit or the max./min. frequency has been
reached. The process regulator will not engage again
until either the error is zero or its sign has changed.
Select Disable [0] if the integrator is to continue
integrating on the deviation, even if it is not possible
to remove the fault by such control.
= factory setting. () = display text [] = value for use in communication via serial communication port
72
VLT® 2800 Series
NOTE
If Disable [0] is selected, it will mean that when
the deviation changes its sign, the integrator
will first have to integrate down from the level
obtained as a result of the former error, before any
change in output frequency occurs.
439 Process PID start frequency
[0]
(PROC START VALUE)
[1]
Value:
f
- f
(parameter 201/202)
MIN
MAX
Par. 201 Output frequency, low limit, f
Function:
When the start signal comes, the variable frequency
drive will react in the form of Open loop and will not
change to Closed loop until the programmed start
frequency is reached. This makes it possible to set a
frequency that corresponds to the speed at which the
process normally runs, which will enable the required
process conditions to be reached sooner.
Description of choice:
Set the required start frequency.
NOTE
If the variable frequency drive is running a the
current limit before the required start frequency
is obtained, the process regulator will not be
activated. For the regulator to be activated anyway, the
[0]
start frequency must be lower to the required output
[1]
frequency. This can be done during operation.
440 Proces PID proportioanl gain
(PROC. PROP. GAIN)
Value:
0.0 - 10.00
Function:
The proportional gain indicates the number of
times the deviation between the setpoint and the
feedback signal is to be applied.
Description of choice:
Quick regulation is obtained by a high gain, but
if the gain is too high, the process may become
unstable due to overshoot.
MG.28.A8.22 - VLT is a registered Danfoss trademark
MIN
0.01
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