Danfoss VLT DMS 300 Manual page 146

439 Process PID start frequency
(PROC START VALUE)
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
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
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.
= factory setting. () = display text [] = value for use in communication via serial communication port
146
Decentral Solutions
441 Process PID integration time
(PROC. INTEGR. T.)
Value:
0.01 - 9999.99 (OFF)
MIN
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.
442 Process PID differentiation time
(PROC. DIFF. TIME)
Value:
0.00 (OFF) - 10.00 sec.
Function:
The differentiator does not react to a constant error.
It only makes a gain when an error changes. The
0.01
quicker the deviation changes, the stronger the gain
from the differentiator. The gain is proportional to
the speed at which the deviation changes.
Description of choice:
Quick regulation is obtained with a long differentiation
time. However, this time may become too long, which
can make the process unstable due to overswing.
443 Process PID diff. gain limit
(PROC. DIFF.GAIN)
Value:
5.0 - 50.0
Function:
It is possible to set a limit for the differentiator gain.
The differentiator gain will increase if there are fast
changes, which is why it can be beneficial to limit this
gain. Thereby a pure differentiator gain is obtained
MG.90.F2.22 - VLT is a registered Danfoss trademark
OFF
0.00 sec.
5.0