Technical data

VLT
®
2800 Series
438 Proces PID anti windup
(PROC ANTI WINDUP)
Value:
Not active (DISABLE)
[0]
✭Active (ENABLE)
[1]
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 initialised 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.
NB!:
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
(PROC START VALUE)
Value:
f
MIN
-f
MAX
(parameter 201/202)
✭ Par. 201 Output frequency, low limit, f
MIN
Function:
When the start signal comes, the frequency converter
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.
NB!:
If the frequency converter 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
start frequency must be lower to the required output
frequency. This can be done during operation.
440 Proces PID proportioanl gain
(PROC. PROP. GAIN)
Value:
0.0 - 10.00
✭ 0.01
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.
441 Process PID integration time
(PROC. INTEGR. T.)
Value:
0.01 - 9999.99 (OFF)
✭ OFF
Function:
The integrator provides an increasing gain at a
constant error between the reference/setpoint and the
feedback signal. The greater the error, the quicker
the integrator frequency contribution will increase.The
integral time is the time needed by the integrator to
make the same change as the proportional gain.
Description of choice:
Quick regulation is obtained at a short integral time.
However, this time may become too short, which can
make the process unstable due to overswing. If the
integral time is long, major deviations from the required
setpoint may occur, since the process regulator will
take a long time to regulate in relation to a given error.
✭ = factory setting. () = display text [] = value for use in communication via serial communication port
MG.28.A9.02 - VLT is a registered Danfoss trademark
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