Danfoss VLT 7000 Series, Руководство пользователя

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VLT® 7000 Booster
Description of choice:
Quick regulation is obtained by a high gain, but if the
gain is too high, the process may become unstable.
424 PID integration time
(PID INTEGR.TIME)
Value:
0.01 - 9999.00 sec. (OFF)
✭
OFF
Function:
The integrator provides a constant change of the
output frequency during constant error between the
reference/setpoint and the feedback signal.
The greater the error, the quicker the integrator
frequency contribution will increase. The integration
time is the time needed by the integrator to reach the
same gain as the proportional gain for a given deviation.
Used in Closed loop [1] (parameter 100).
Description of choice:
Fast regulation is obtained in connection with a short
integration time. However, this time
may be too short, which means that the process may
be destabilised as a result of overswings.
If the integral time is long, major deviations from
the required set point may occur, since the
process regulator will take a long time to regulate
in relation to a given error.
NB!:
Some value other than OFF must be set or
the PID will not function correctly.
425 PID differentiation time
(PID DIFF. TIME)
Value:
0.00 (OFF) - 10.00 sec.
✭
OFF
Function:
The differentiator does not react to a constant error. It
only contributes when the error changes. The quicker
the error changes, the stronger the contribution from
the differentiator will be. This influence is proportional
to the speed by which the deviation changes.
Used in Closed loop [1] (parameter 100).
Description of choice:
Fast regulation can be obtained by means of a
long differentiation time. However, this time may
be too long, which means that the process may be
destabilised as a result of overswings.
426 PID differentiator gain limit
(PID DIFF. GAIN)
Value:
5.0 - 50.0
✭
5.0
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 obtaining a pure differentiator gain at
slow changes and a constant differentiator gain where
quick changes to the deviation are made.
Used in Closed loop [1] (parameter 100).
Description of choice:
Select a limit to differentiator gain as required.
427 PID lowpass filter time
(PID FILTER TIME)
Value:
0.01 - 10.00
✭
0.01
Function:
Oscillations on the feedback signal are dampened by
the lowpass filter in order to reduce their impact on
the process regulation. This can be an advantage
if there is a lot of noise on the signal.
Used in Closed loop [1] (parameter 100).
Description of choice:
Select the desired time constant (
τ
). If a time constant
(
τ
) of 0.1 s is programmed, the break 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, the Process regulator will not react.
✭
= factory setting. () = display text [] = value for use in communication via serial communication port
MG.70.A1.02 - VLT is a registered Danfoss trademark
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