AKD 2800
Programming
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.
444 Process PID lowpass filter time
(PROC FILTER TIME)
Value:
0.02 - 10.00
✭
0.02
Function:
Noise in the feedback signal is dampened by a first
order lowpass filter to reduce the noise
’
s impact on
the process regulation. This can be an advantage
e.g. if there is a lot of noise on the signal.
Description of choice:
Select the required time constant (t). If a time constant
(t) of 0.1 s is programmed, the cut-off frequency
for the lowpass filter will be 1/0.1 = 10 RAD/sec.,
corresponding to (10 / 2 x
π
) = 1.6 Hz. The process
regulator will thus only regulate a feedback signal
that varies by a frequency lower than 1.6 Hz. If the
feedback signal varies by a higher frequency than 1.6
Hz, it will be dampened by the lowpass filter.
✭
= factory setting. () = display text [] = value for use in communication via serial communication port
MG.28.H2.02 -
37