VLT
®
FCM Series
Programming
437 Process PID Normal/inverse control
(PROC NO/INV CTRL)
Value:
✭
Normal (NORMAL)
[0]
Inverse (INVERSE)
[1]
Function:
It is possible to choose whether the process
regulator is to increase/reduce the output frequency
if there is a difference between the reference
signal and the feedback signal.
Used together with
Process, closed loop
mode
(parameter 100).
Description of choice:
If the FC motor is to reduce the output frequency in
case the feedback signal increases, select
Normal
[0].
If the FC motor is to increase the output frequency in
case the feedback signal increases, select
Inverse
[1].
438 Process PID anti windup
(PROC ANTI WINDUP)
Value:
Disable (DISABLE)
[0]
✭
Enable (ENABLE)
[1]
Function:
It is possible to select whether the process regulator is
to continue regulating on an error even if it is not possible
to increase/reduce the output frequency. Used together
with
Process, closed loop mode
(parameter 100).
Description of choice:
The factory setting is
Enable
[1], which means that
the integration link is adjusted in relation to the
actual output frequency if either the current 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 an error, even if it is not possible to
remove the fault by such regulation.
NB!:
If
Disable
[0] is selected, it will mean that when
the error 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 to the output frequency occurs.
439 Process PID start frequency
(PROC START VALUE)
Value:
f
MIN
-f
MAX
(PARAMETER 201 AND 202)
[X.X]
✭
parameter 201
Function:
When the start signal comes, the FC motor will react
in the form of
Speed, open loop mode
following the
ramp. Only when the programmed start frequency
has been obtained, will it change over to
Process,
closed loop mode
. In addition, it is 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.
Used together with
Process, closed loop
mode
(parameter 100).
Description of choice:
Set the required start frequency.
NB!:
If the FC motor is running at the current limit
before the desired start frequency is obtained,
the process regulator will not be activated.
For the regulator to be activated anyway, the start
frequency must be lowered to the required output
frequency. This can be done during operation.
440 Process PID proportional gain
(PROC. PROP. GAIN)
Value:
0.00 (OFF) - 10.00
[0 - 1000]
✭
0.01
[1]
Function:
The proportional gain indicates the number of
times the error between the set point and the
feedback signal is to be applied.
Used together with
Process, closed loop
mode
(parameter 100).
Description of choice:
Quick regulation is obtained by a high gain, but if the
gain is too high, the process may become unstable.
441 Process PID integral time
(PROC. INTEGR. T.)
Value:
0.01 - 9999 sec. (OFF)
[1 - 999900]
✭
9999 sec.
[999900]
✭
= factory setting. () = display text [] = value for use in communication via serial communication port
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