Description of choice:
Set the output frequency (F2) that is to match the second output voltage
(U2), parameter 425
U2 voltage
.
427
U3 voltage
Value:
0.0 - 999.0 V
par. 103
Function:
See parameter 423
U1 voltage
.
Description of choice:
Set the output voltage (U3) that is to match the third output frequency
(F3), parameter 428
F3 frequency
.
428
F3 frequency
Value:
Par. 426
F2 frequency
- 1000 Hz
Par. 104
Motor frequency
Function:
See parameter 423
U1 voltage
.
Description of choice:
Set the output frequency (F3) that is to match the third output voltage
(U3), parameter 427
U3 voltage
.
NB!
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
Value:
Normal (normal)
[0]
Inverse (inverse)
[1]
Function:
It is possible to choose whether the process regulator is to increase/re-
duce the output frequency if there is a deviation between the reference/
setpoint and the actual process mode.
Description of choice:
If the adjustable frequency drive is to reduce the output frequency in case
the feedback signal increases, select
Normal
[0].If the adjustable fre-
quency drive is to increase the output frequency in case the feedback
signal increases, select
Inverse
[1].
438
Proces PID anti windup
Value:
Not active (DISABLE)
[0]
Active (ENABLE)
[1]
Function:
It is possible to select whether the process regulator is to continue reg-
ulating 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 inte-
grating 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 fre-
quency occurs.
439
Process PID start frequency
Value:
f
MIN
- f
MAX
(parameter
201/202)
Par. 201
Output frequency, low limit, f
MIN
Function:
When the start signal comes, the adjustable frequency drive will react in
the form of
Open loop
and will not change to
Closed loop
until the pro-
grammed 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 adjustable frequency drive is running a the cur-
rent limit before the required start frequency is ob-
tained, the process regulator will not be activated. For
the regulator to be activated anyway, the start fre-
quency must be lower to the required output frequen-
cy. This can be done during operation.
440
Proces PID proportioanl gain
Value:
0.0 - 10.00
0.01
Function:
The proportional gain indicates the number of times the deviation be-
tween 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
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
4 Programming
VLT
®
Decentral FCD 300 Design Guide
96
MG.90.S1.02 - VLT
®
is a registered Danfoss trademark
4
